Effects of Lactic Acid Bacteria and Fructooligosaccharides on Growth Performance,Nutrient Digestibility and Serum Biochemical Indices of Arctic Foxes (Alopex lagopus) during Early Growth Period北大核心CSCD

This experiment was conducted to study the effects of dietary lactic acid bacteria (LAB) and fructooligosaccharides (FOS) on growth performance, nutrient digestibility and serum biochemical indices of Arctic foxes (Alopex lagopus) during early growth period. Sixty male post-litter Arctic foxes with the average body weight of (1.16±0.15) kg and at the age of (45±3) days were randomly assigned to 4 groups with 3 replicates per group and 5 foxes per replicate. The foxes were fed the following diets, respectively: basal diet (control group), basal diet+3×109 CFU / kg LAB (LAB group), basal diet+5 g / kg FOS (FOS group) and basal diet+3×109 CFU / kg LAB+5 g / kg FOS (LAB+FOS group). The experiment lasted for 30 days. The results showed as follows: 1) on the days 1 to 15, the diarrhea rate of foxes in the LAB group and LAB+FOS group was significantly lower than that in the control group and FOS group (P<0.05). On the days 16 to 30, the average daily gain of foxes in the LAB+FOS group was significantly higher than that in the control group and FOS group (P<0.05), but had no significant difference with LAB group (P>0.05); the diarrhea rate of foxes in the LAB+FOS group was significantly lower than that in the control group and FOS group (P<0.05), but had no significant difference with LAB group (P>0.05); compared with the FOS group, the feed to gain ratio of foxes in the LAB+FOS group was significantly decreased (P<0.05). 2) The dry matter digestibility of foxes in the LAB + FOS group was significantly higher than that in the control group and FOS group (P < 0.05), but had no significant difference with LAB group (P>0.05). There were no significant differences in nitrogen intake, fecal nitrogen, urine nitrogen, nitrogen deposition, net protein utilization and protein biological value among all groups (P>0.05). 3) Serum total protein (TP) content of foxes in the LAB+FOS group was significantly higher than that in the FOS group (P<0.05), but had no significant difference with control group and LAB group (P>0.05). Serum albumin (ALB) content of foxes in the LAB group was significantly higher than that in the control group and FOS group (P<0.05), but had no significant difference with LAB+ FOS group (P>0.05). Serum urea nitrogen (UN) content of foxes in the LAB+FOS group was significantly decreased compared with the control group (P < 0. 05). In conclusion, the combined supplementation of 3 × 109 CFU / kg LAB and 5 g / kg FOS in the diet is beneficial to reduce diarrhea rate, improve dry matter digestibility, improve body immune level, and promote the growth of Arctic foxes during early growth period. © 2023 Chinese Journal of Urology. All rights reserved.     

Changes of Rumen Microbiota Density and Physicochemical Properties at Different pH北大核心CSCD

The aim of this experiment was to investigate the changes of rumen microbiota density and physicochemical properties at different pH. Five Holstein cows in dry milk period were selected as rumen fluid donors. Using in vitro method, five treatments were set according to the criteria of rumen acidosis, and the pH of culture medium was 6.5, 5.8, 5.5, 5.2 and 5.0, respectively, with five replicates in each treatment. After three hours of incubation, the changes of rumen microbiota density and physicochemical properties were measured. The results showed as follows: 1) with the decrease of pH, the rumen microbiota density showed a fluctuation change of first decreasing, then increasing and then decreasing, and the microbiota density in pH 5.8 treatment was significantly lower than that in pH 6.5 treatment (P<0.05). When pH was 5.2, the rumen microbiota density was the highest, which was significantly higher than that in the other treatments (P<0.05). 2) With the decrease of pH, the intracellular H+-ATPase activity in rumen microbiota was firstly increased and then decreased, but there was no significant difference among all treatments (P>0.05). 3) The intracellular ATP content in rumen microbiota was not significantly affected by different pH treatments (P>0.05). 4) With the decrease of pH, the intracellular protein content in rumen microbiota was gradually increased (P<0.05). 5) With the decrease of pH, the intracellular pH (pHi) and cellular transmembrane pH difference (ΔpH) in rumen microbiota were firstly increased and then decreased, and the pHi and ΔpH in pH 5.5 and 5.2 treatments were significantly higher than those in the other three treatments (P<0.05). 6) With the decrease of pH, the cell membrane permeability of rumen microbiota was gradually increased, except for pH 5.8 treatment, the other treatments were significantly higher than pH 6.5 treatment (P<0.05). In conclusion, the rumen microbiota can increase the intracellular H+-ATPase activity and protein content, consume ATP, and change pHi and ΔpH in response to external pH decline. When pH decreases to 5.5, the membrane permeability and pHi of rumen microbiota increase significantly, indicating that they are running to be subjected to more serious acid stress. The density of rumen microbiota fluctuates with the decrease of pH, and when pH decreases to 5.2, the density of rumen microbiota is the highest. © 2023 Authors. All rights reserved.     

Effects of Dietary Tributyrin on Growth Performance,Serum Biochemical Indices,Immune Function and Antioxidant Capacity of Juvenile Yellow Catfish (Pelteobagrus fulvidraco)北大核心CSCD

This experiment was conducted to investigate the effects of dietary tributyrin on growth performance, serum biochemical indices, immunity function and antioxidant capacity of juvenile yellow catfish (Pelteobagrus fulvidraco). A total of 480 juvenile yellow catfish with an initial body weight of (5.53±0.02) g were selected and randomly divided into 4 groups with 3 replicates in each group, and 40 fish in each replicate. Four isonitrogenous and isolipid experimental diets were fed with 0 (G0), 500 (G1), 1 000 (G2) and 2 000 mg/kg (G3) triglyceride, respectively. The experiment lasted for 56 days. The results showed as follows: 1) weight gain rate and feed efficiency rate in G2 group were significantly higher than those in other groups (P<0.05). The fatness in G1 group was significantly lower than that in G0 and G3 groups (P<0.05), but there was no significant difference between G1 group and G2 group (P>0.05). 2) The serum glucose content in G3 group was significantly higher than that in G1 and G2 groups (P<0.05), and there were no significant differences in the serum contents of total protein, albumin, globulin, triglyceride, urea nitrogen and the activities of alanine aminotransferase and aspartate aminotransferase among all groups (P>0.05). 3) Compared with G0 group, serum lysozyme activity in G1, G2 and G3 groups was significantly increased (P<0.05), serum alkaline phosphatase activity in G1 and G2 groups was significantly increased (P<0.05), and serum immunoglobulin M content in G2 group was significantly higher than that in G3 group (P<0.05). There was no significant difference in serum complement C3 content among all groups (P>0.05). 4) Compared with G0 group, serum total antioxidant capacity in G1 group was significantly increased (P<0.05), and serum super-oxide dismutase activity in G1, G2 and G3 groups was significantly increased (P<0.05). The serum catalase activity in G3 group was significantly higher than that in G0, G1 and G2 groups (P<0.05), but there were no significant differences in serum glutathione peroxidase activity, glutathione and malondialdehyde contents among all groups (P>0.05). In conclusion, dietary supplementation of 500 to 2 000 mg/kg triglyceride can significantly improve non-specific immune and antioxidant capacity of yellow catfish, and dietary supplementation of 1 000 mg/kg triglyceride can significantly improve weight gain rate and feed efficiency of yellow catfish. Combined with the comprehensive evaluation of growth performance, serum immunity and antioxidant indexes, the optimal supplemental level of triglyceride in yellow catfish diet is 1 000 mg/kg. © 2023 Authors. All rights reserved.     

Effects of Compound Bacteria Preparation on Fermentation Quality and Rumen Fermentation Characteristics of Phragmites australis Silage北大核心CSCD

The purpose of this study was to investigate the effects of compound bacteria preparation (including homogeneous Lactobacillus/heterogeneous Lactobacillus, Bacillus subtilis and Aspergillus niger as well as their compatibility) on nutrient composition, fermentation quality and rumen fermentation characteristics of Phragmites australis silage. Taking growing Phragmites australis from Dongting lake as silage material, five groups were set up, which were blank group (CK group), lactic acid bacteria group (LA group, supplemented with Lactobacillus plantarum, Pediococcus pentosaceus and Lactobacillus buchneri), lactic acid bacteria+Bacillus subtilis group (LA+BS group), lactic acid bacteria+Aspergillus niger group (LA+AN group) and lactic acid bacteria+Bacillus subtilis+Aspergillus niger group (LA+BS+AN group), and each group had 3 replicates. The supplemental level of lactic acid bacteria was 1.5×108 CFU/kg silage raw materials, and the supplemental levels of Aspergillus niger and Bacillus subtilis were 1.0×108 CFU/kg silage raw materials (all were based on fresh weight of silage raw materials). After 60 days of silage, the nutrient composition and fermentation quality of Phragmites australis silage were determined, and the rumen fermentation characteristics were evaluated by in vitro fermentation and in vivo degradation. The results showed as follows: 1) the contents of dry matter and ash in LA, LA+BS and LA+AN groups were significantly lower than those in CK group (P<0.05), and the crude protein content in LA+BS, LA+AN and LA+BS+AN groups was significantly higher than that in CK and LA groups (P<0.05). 2) The silage sensory evaluation scores of all groups were 60 to 70 points, and the ratings were good. The comprehensive scores of fermentation quality in LA+BS and LA+AN groups were higher, among which, the ammonia nitrogen to total nitrogen ratio, acetic acid content and acetic acid to total acid ratio in LA+AN group were significantly decreased compared with CK group (P<0.05), while the lactic acid content and lactic acid to total acid ratio were significantly increased compared with CK group (P<0.05). 3) The dry matter disappearance rate and total gas production of in vitro fermentation in LA+AN group were significantly higher than those in the other groups (P<0.05), and in vitro fermentation parameters such as volatile fatty acid contents in fermentation liquid were improved. 4) The rumen fermentation dry matter degradation rate in LA+AN and LA+BS+AN groups at 8, 24 and 48 h was significantly higher than that in the other three groups (P<0.05). In conclusion, the combined application of lactic acid bacteria and Aspergillus niger with supplemental levels in this experiment has the best effect on the quality of Phragmites australis silage and rumen fermentation characteristics. © The Author(s) 2023.     

Responsive changes of rumen microbiome and metabolome in dairy cows with different susceptibility to subacute ruminal acidosis

Subacute ruminal acidosis(SARA)represents one of the most important digestive disorders in intensive dairy farms,and dairy cows are individually different in the severity of SARA risk.The objectives of the current study were to investigate differences in the ruminal bacterial community and metabolome in dairy cattle with different susceptibility to SARA.In the present study,12 cows were initially enrolled in the experiment.Based on average ruminal pH,4 cows with the lowest ruminal pH were assigned to the susceptible group(SUS,pH=5.76,n=4)and 4 cows with the highest ruminal pH assigned to the tolerant group(TOL,pH=6.10,n=4).Rumen contents from susceptible(SUS,n=4)and tolerant(TOL,n=4)dairy cows were collected through rumen fistula to systematically reveal the rumen microbial and metabolic alterations of dairy cows with different susceptibility to SARA using multi-omics approaches(16S and 18S rRNA gene sequencing and metabolome).The results showed that despite being fed the same diet,SUS cows had lower ruminal pH and higher concentrations of total volatile fatty acids(VFA)and propionate than TOL cows(P<0.05).No significant differences were observed in dry matter intake,milk yield,and other milk compositions between the SUS and TOL groups(P>0.05).The principal coordinates analysis based on the analysis of molecular variance indicated a significant difference in bacterial composition between the two groups(P=0.01).More specifically,the relative abundance of starch-degrading bacteria(Prevotella spp.)was greater(P<0.05),while the proportion of fiber-degrading bacteria(unclassified Ruminococcaceae spp.,Ruminococcus spp.,Papillibacter,and unclassified Family_-XIII)was lower in the rumen of SUS cows compared with TOL cows(P<0.05).Community analysis of protozoa showed that there were no significant differences in the diversity,richness,and community structure(P>0.05).Metabolomics analysis revealed that the concentrations of organic acids(such as lactic acid),biogenic amines(such as histamine),and bacterial degradation products(such as hypoxanthine)were significantly higher in the SUS group compared to the TOL group(P<0.05).These findings revealed that the higher proportion of starch-degrading bacteria/lower fiber-degrading bacteria in the rumen of SUS cows resulted in higher VFA-producing capacity,in particular propionate.This caused a disruption in metabolic homeostasis in the rumen which might be the reason for the higher susceptibility to SARA.Overall,these findings enhanced our understanding of the ruminal microbiome and metabolic changes in cows susceptible to SARA.     

Effects of Dietary Sodium Acetate on Lactation Performance and Rumen Microbiota of Dairy Goats北大核心CSCD

This experiment was conducted to investigate the effects of dietary sodium acetate on lactation performance and rumen microbiota of dairy goats. Fifteen healthy Xinong Saanen dairy goat ewes with similar body weight of (53.54±3.07) kg, the same parity (2 parities) and in mid-lactation [(60±5) d] were randomly divided into 3 groups with 5 replicates in each group. Dairy goats in the control group were fed a basal diet, and those in the experimental groups were fed the basal diet supplemented with 30 (experimental group I) and 60 g/ (d.head) (experimental group II) sodium acetate, respectively. The pre-trial period lasted for 7 days and the experimental period lasted for 21 days. The milk yield of dairy goats was recorded during the experiment. At the end of the experiment, milk samples were collected to analyze the changes in milk composition, and rumen contents of dairy goats were collected from two groups (control group and experimental group II) with significant differences in milk fat percentage. Gas chromatography and 16S rDNA sequencing technology were used to analyze the rumen fermentation parameters and rumen microbial composition and structure of dairy goats. The results showed as follows: 1) compared with the control group, dietary sodium acetate extremely significantly increased the daily milk yield of dairy goats (P<0.01), and the daily milk yield in experimental groups I and II was increased by 0.29 and 0.22 kg, respectively (P<0.01); in experimental group II, the milk fat percentage was significantly increased by 1.30 percentage points (P<0.01), and the non-fat solid content in milk was increased by 3.10% (P>0.05). 2) Compared with the control group, the rumen butyric acid content of dairy goats in experimental group II was significantly decreased (P<0.01), and there was no significant difference in rumen pH, the other volatile fatty acid content and acetic acid to propionic acid ratio (P>0.05). 3) Compared with the control group, the Sobs index, Chao1 index and Ace index of rumen microbiota in experimental group II were significantly increased (P<0.05); the results of similarity analysis (ANOSIM) also showed that there were significant differences in the structure of rumen microbiota between the two groups (P<0.05). 16S rDNA sequencing results showed that at the phylum level, Bacteroidetes and Firmicutes were the dominant phyla in the rumen of the two groups of dairy goats; at the genus level, Prevotella_1 was the dominant genus in the rumen. Compared with the control group, the relative abundances of Ruminococcus_1, Ruminococcaceae_UCG-005, Prevotellaceae_UCG-004 and Lachnoclostridium_12 in rumen of dairy goats in experimental group II were significantly increased (P<0.05), while the relative abundances of Succiniclasticum and Methanobrevibacter in rumen was significantly decreased (P<0.05). 4) The results of correlation analysis showed that rumen microbiota was correlated with daily milk yield, milk fat percentage, milk protein percentage and non-fat solid content of dairy goats. In conclusion, dietary 60 g/ (d.head) sodium acetate can significantly increase the daily milk yield and milk fat percentage, significantly reduce rumen butyrate content, and improve the lactation performance of dairy goats by improving rumen microbial composition and structure. © 2023 Authors. All rights reserved.     

Effects of dietary concentrate level and chromium-methionine supplementation on ruminal fermentation,and ruminal bacterial and fatty acid composition in Tan lambs北大核心CSCD

This study evaluated the effects of dietary concentrate level and chromium methionine(Cr-Met)supplementation on ruminal fermentation and fatty acid composition, and ruminal bacteria abundance in Tan lambs. Forty male Tan lambs [(21.00±1.23) kg body weight, 5 months of age] were randomly assigned to four treatment groups with 10 lambs in each treatment. The treatments were: a low-concentrate (LC) diet (concentrate:forage, 35:65) without Cr-Met supplementation; a high-concentrate (HC) diet (concentrate:forage, 55:45) without Cr-Met supplementation; groups fed the HC diet with 0.75 or 1.50 g·d-1·lamb-1 Cr-Met (HCM and HCH, respectively). Ruminal fluid was collected on day 65 with an oral stomach tube about 3 h after the morning feed and samples used for fermentation analysis, fatty acid composition determination and bacterial DNA extraction. It was found that: 1) Ruminal pH, acetate proportion and acetate:propionate were greater (P<0.05) with the LC diet whereas microbial crude protein, propionate and valerate proportions were greater (P<0.05) with the HC diet. The acetate:propionate was greater (P<0.05) in the HCM group than in the HC group. 2) For the HC diet, the DNA abundances of Butyrivibrio fibrisolvens vaccenic acid subgroup (Butyrivibrio VA) and Ruminococcus flavefaciens were decreased (P<0.05), compared with the LC diet, whereas the DNA abundance of Anaerovibrio lipolytica was increased (P<0.05). For lambs fed the HC diet, DNA abundances of B. fibrisolvens stearic acid subgroup, Butyrivibrio VA, Butyrivibrio proteoclasticus, and A. lipolytica showed a linear decrease (P<0.05) with increasing Cr-Met supplementation level; However, the DNA abundance of R. flavefaciens showed a linear increase (P<0.05). 3) Compared with the LC group, the concentrations of t11 C18:1, trans C18:1, c9t11 CLA, t10c12 CLA, C18:2n6, and C18:3n3 were decreased by the HC diet without Cr-Met supplementation whereas the concentration of C18:0 was increased. There was a linear increase in t11 C18:1 and trans C18:1 with increasing Cr-Met supplementation level in lambs fed the HC diet. The results suggest that the HC diet inhibited the growth of ruminal bacteria involved in the ruminal biohydrogenation process, and the addition of Cr-Met had a potentially positive effect on conjugated linoleic acid (CLA) synthesis in body tissue. © 2022, Editorial Office of Acta Prataculturae Sinica. All rights reserved.     

Effects of Faba Bean Supplementation on Growth Performance,Intestinal Digestive Enzyme Activities,Intestinal Morphology and Intestinal Flora of Tilapia (Oreochromis niloticus)北大核心CSCD

This study was conducted to investigate the effects of faba bean supplementation on the growth performance, intestinal digestive enzyme activities, intestinal morphology and intestinal flora of tilapia (Oreochromis niloticus). A total of 600 genetic improvement of farmed tilapia with an initial body weight of (500.23± 0.34) g were randomly divided into 4 groups with 3 replicates per group and 50 fish per replicate. Four isonitrogenous and isolipidic experimental diets containing 0 (C0 group, as control), 15% (C15 group), 30% (C30 group) and 60% (C60 group) faba bean were fed to fish during the 100-d feeding trial. Results showed as follows: 1) there were no significant differences in the weight gain rate, specific growth rate, feed coefficient ratio and hepatosomatic index among the groups (P>0.05), the protein efficiency ratio and survival rate in C60 group were significantly higher than those in C0 and C15 groups (P<0.05). 2) There were no significant differences in the activities of amylase, lipase and trypsin among the groups (P>0.05). 3) Compared with the C0 group, the C15, C30 and C60 groups had significantly lower intestinal villus height, villus thickness and muscle thickness (P<0.05). 4) The Simpson index of intestinal flora of tilapia in C15, C30 and C60 groups was lower than that in C0 group, and the difference was significant between C30 and C0 groups (P< 0.05). 5) The intestinal core flora of the four groups of tilapia were mainly Cyanobacteria, Actinobacteriota, Firmicutes, Proteobacteria and Fusobacteriota. Compared with the C0 group, the relative abundance of Proteobacteria in C15, C30 and C60 groups had a significant reduction (P<0.05), and the relative abundances of Fusobacteriota and Cetobacterium in C15 and C60 groups had a significant reduction (P<0.05). To conclude, under the conditions of isonitrogenous and isolipidic, diets supplemented with 15% to 60% faba bean have no significant effects on the growth performance and intestinal digestive enzyme activities of tilapia, but can significantly reduce the intestinal villi height, villus width and muscle thickness, decrease the relative abundance of Proteobacteria and the diversity of intestinal flora. © 2023 Authors. All rights reserved.     

Solid-state fermentation of corn-soybean meal mixed feed with Bacillus subtilis and Enterococcus faecium for degrading antinutritional factors and enhancing nutritional value

Background: Corn and soybean meal(SBM) are two of the most common feed ingredients used in pig feeds.However, a variety of antinutritional factors(ANFs) present in corn and SBM can interfere with the bioavailability of nutrients and have negative health effects on the pigs. In the present study, two-stage fermentation using Bacillus subtilis followed by Enterococcus faecium was carried out to degrade ANFs and improve the nutritional quality of corn and SBM mixed feed. Furthermore, the microbial composition and in vitro nutrient digestibility of inoculated mixed feed were determined and compared those of the uninoculated controls.Results: During the fermentation process, B. subtilis and lactic acid bacteria(LAB) were the main dominant bacteria in the solid-state fermented inoculated feed, and fermentation produced a large amount of lactic acid(170 mmo L/kg),which resulted in a lower pH(5.0 vs. 6.4) than the fermented uninoculated feed. The amounts of soybean antigenic proteins(β-conglycinin and glycinin) in mixed feed were significantly decreased after first-stage fermentation with B. subtilis. Inoculated mixed feed following two-stage fermentation contained greater concentratioin of crude protein(CP), ash and total phosphorus(P) compared to uninoculated feed, whereas the concentrations of neutral detergent fiber(NDF), hemicellulose and phytate P in fermendted inoculated feed declined(P 0.05) by 38%, 53%, and 46%,respectively. Notably, the content of trichloroacetic acid soluble protein(TCA-SP), particularly that of small peptides and free amino acids(AA), increased 6.5 fold following two-stage fermentation. There was no difference in the total AA content between fermented inoculated and uninoculated feed. However, aromatic AAs(Phe and Tyr) and Lys in inoculated feed increased, and some polar AAs, including Arg, Asp, and Glu, decreased compared with the uninoculated feed. In vitro dry matter and CP digestibility of inoculated feed improved(P 0.05) compared with the uninoculated feed.Conclusions: Our results suggest that two-stage fermentation using B. subtilis followed by E. faecium is an effective approach to improve the quality of corn-soybean meal mixed feed.     

Quantitative analysis of ruminal methanogenic microbial populations in beef cattle divergent in phenotypic residual feed intake（RFI）offered contrasting diets

Background：Methane（CH_4） emissions in cattle are an undesirable end product of rumen methanogenic fermentative activity as they are associated not only with negative environmental impacts but also with reduced host feed efficiency.The aim of this study was to quantify total and specific rumen microbial methanogenic populations in beef cattle divergently selected for residual feed intake（RFI） while offered（i） a low energy high forage（HF） diet followed by（ii） a high energy low forage（LF） diet.Ruminal fluid was collected from 14 high（H）and 14 low（L） RFI animals across both dietary periods.Quantitative real time PCR（qRT-PCR） analysis was conducted to quantify the abundance of total and specific rumen methanogenic microbes.Spearman correlation analysis was used to investigate the association between the relative abundance of methanogens and animal performance,rumen fermentation variables and diet digestibility.Results：Abundance of methanogens,did not differ between RFI phenotypes.However,relative abundance of total and specific methanogen species was affected（P〈 0.05） by diet type,with greater abundance observed while animals were offered the LF compared to the HF diet.Conclusions：These findings suggest that differences in abundance of specific rumen methanogen species may not contribute to variation in CH_4 emissions between efficient and inefficient animals,however dietary manipulation can influence the abundance of total and specific methanogen species.     

Effects of Dietary Ampitheoe sp. Powder on Growth and Lipid Contents of Litopenaeus vannamei北大核心CSCD

This experiment was conducted to investigate the effects of dietary Ampitheoe sp. powder on the growth and the contents of astaxanthin, triglyceride (TG), total cholesterol (TCHO) and fatty acids of Litopenaeus vannamei. A total of approximately 6 777 L. vannamei with an initial body weight of (1. 80 ± 0.72) g were randomly divided into 3 groups, and there were 3 replicates (753 shrimp per replicate) in each group. Those shrimp fed diets containing 0 (D0 group), 8. 25% (D8. 25 group) and 33% (D33. 00 group) Ampitheoe sp. powder, respectively. The feeding trial lasted for 40 days. The results showed as follows: 1) the final body weight, weight gain rate, specific growth rate, yield and survival rate in D33.00 group were significantly higher than those in D0 group (P <0.05), whereas the feed conversion ratio was significantly lower than that in D0 group (P <0.05) . However, there was no significant difference between D33.00 group and the D8. 25 group in those indexes (P >0.05) . 2) The astaxanthin content in carapace, hepatopancreas and muscle of L. vannamei in D8.25 and D33. 00 groups was significantly higher than that in D0 group (P < 0. 05); that in D33.00 group was significantly higher than that in D8. 25 group (P < 0. 05) . 3) TG content in haemolymph, hepatopancreas and muscle in D8. 25 and D33. 00 groups was significantly lower than that in D0 group (P < 0.05); the TCHO content in hepatopancreas in D8. 25 group was significantly higher than that in D0 and D33.00 groups (P <0.05); TCHO content in muscle in D33.00 group was significantly higher than that in D0 group (P <0.05) . 4) The contents of eicosapentaenoic acid (EPA) and arachidonic acid (AA) in hepatopancreas in D33.00 group were significantly higher than those in D0 group (P <0.05) . The EPA content in muscle in D33.00 group was significantly higher than that in D0 group (P < 0. 05) . In conclusion, adding Ampitheoe sp. powder into the diet can improve the growth performance, the contents of astaxanthin, EPA and AA in L. vannamei, and affect the accumulation of TG and TCHO, which can be used as a functional diet in aquaculture. Considering the cost, the supplementation level of 8. 25% Ampitheoe sp. powder is more appropriate. © 2023 Chinese Journal of Pediatric Surgery. All rights reserved.     

Effects of Dietary Quercetin on Growth Performance,Digestive Enzyme Activities,Immune and Antioxidant Functions of Cyprinus carpio北大核心CSCD

This experiment was conducted to investigate the effects of different dietary levels of quercetin on growth performance, digestive enzyme activities, immune and antioxidant functions of juvenile Cyprinus carpio. Three hundred juvenile Cyprinus carpio with an initial body weight of (26.00±0.50) g were randomly divided into 5 groups with 3 replicates per group and 20 fish per replicate. The control group (T1 group) was fed a basal diet, and the experimental groups were fed the basal diets supplemented with 50 (T2 group), 100 (T3 group), 200 (T4 group) and 400 mg/ kg (T5 group) quercetin, respectively. The experiment lasted for 8 weeks. The results showed as follows: 1) compared with T1 group, the final body weight of juvenile Cypri⁃ nus carpio in T3 and T4 groups was significantly increased (P < 0. 05), the weight gain rate and specific growth rate in T3 group were significantly increased (P<0.05), and the feed coefficient in all experimental groups was significantly decreased (P<0.05), which in T3 group was the lowest. With the specific growth rate as the evaluation index, according to the cubic regression model analysis, the optimal supplemental level of quercetin in the diet for Cyprinus carpio was 124.02 mg/ kg. 2) The activities of intestinal protease, lipase and amylase in T3 group were significantly higher than those in the other groups (P<0.05). 3) Compared with T1 group, the serum acid phosphatase (ACP) activity and complement 3 (C3) content in T3 group were signifi⁃ cantly increased (P<0.05); the serum complement 4 (C4) content in T3 group was the highest, and signifi⁃ cantly higher than that in the other groups (P<0.05); the serum lysozyme (LZM) activity and immunoglobu⁃ lin M (IgM) content in T3 and T4 groups were significantly increased (P<0.05), and the serum LZM activity in T3 group was significantly higher than that in T4 group (P<0.05). 4) Compared with T1 group, the activi⁃ ties of liver superoxide dismutase (SOD) and catalase (CAT) in T3 group were significantly increased (P< 0.05); the liver glutathione peroxidase (GPX) activity in T3 group was the highest, and significantly higher than that in the other groups (P<0.05); the liver total antioxidant capacity (T⁃AOC) in T3 and T4 groups was significantly increased (P<0.05); the liver malondialdehyde (MDA) content in T2, T3 and T4 groups was significantly decreased (P<0.05). In conclusion, the optimal supplemental level of quercetin can improve the growth performance, digestive enzyme activities, immune and antioxidant functions of juvenile Cyprinus carpio, and the optimal supplemental level is 100 mg / kg. © 2023 Chinese Journal of Clinical Research. All rights reserved.     

Nitrogen partitioning and microbial protein synthesis in lactating dairy cows with different phenotypic residual feed intake

Background: Residual feed intake(RFI) is an inheritable measure of feed efficiency that is independent on level of production. However, physiological and metabolic mechanisms underlying divergent RFI are not fully elucidated.This study was conducted to investigate dietary nitrogen(N) partitioning and microbial protein synthesis in lactating dairy cows divergent in phenotypic RFI.Results: Thirty Holstein dairy cows(milk yield = 35.3 ± 4.71 kg/d; milk protein yield = 1.18 ± 0.13 kg/d; mean ± standard deviation) were selected for the experiment to derive RFI. After the RFI measurement period of 50 d, the 10 lowest RFI cows and 8 highest RFI cows were selected. The low RFI cows had lower dry matter intake(DMI, P 0.05) than the high RFI cows, but they produced similar energy-corrected milk. The ratios of milk to DMI(1.41 vs. 1.24, P 0.01) and energy-corrected milk to DMI(1.48 vs. 1.36, P 0.01) were greater in low RFI cows than those in the high RFI cows. The low RFI cows had lower milk urea nitrogen than that in the high RFI cows(P = 0.05). Apparent digestibility of nutrients did not differ between two groups(P 0.10). Compared with high RFI animals, the low RFI cows had a lower retention of N(5.72 vs. 51.4 g/d, P 0.05) and a higher partition of feed N to milk N(29.7% vs. 26.5%, P 0.05).Conclusions: The results suggest that differences in N partition, synthesis of microbial protein, and utilization of metabolizable protein could be part of the mechanisms associated with variance in the RFI.     

Effects of fermented soybean residues on growth performance,apparent nutrient digestibility,meat quality and serum biochemical indexes of Hu sheep北大核心CSCD

The experiment was conducted to study the effects of fermented soybean residues on growth performance, apparent nutrient digestibility, meat quality and blood physiological indexes of Hu sheep, and to investigate the value of fermented soybean residues in the production of meat sheep. In the present study, twenty-one healthy male Hu sheep with similar body weight were selected and randomly allocated into a basal diet （control） group, a soybean residue group （basal diet+20% soybean residue, SR） or a fermented soybean residues group （basal diet+20% fermented soybean residues, FSR）, with 7 animals in each group. The experiment lasted for 49 days, including a 7-day adaptation period. The results were as follows: 1）Compared with the control and SR groups, addition of 20% fermented soybean residues in the diet （FSR） significantly increased the average daily weight gain of Hu sheep （P< 0.05） and significantly reduced the weight gain cost （P<0.05）. 2） The apparent digestibility of dry matter （DM）, crude protein （CP） and neutral detergent fiber （NDF） of Hu sheep in the fermented soybean residues group was significantly higher than that in other groups （P<0.05）. 3） Compared with the SR group, the carcass weight of the FSR group was increased （P<0.05）, while the dressing percentage, meat redness values of the FSR group were greater than those of the other groups （P<0.05）, and the drip loss was lower than other groups （P<0.05）. 4） Compared with the control and SR groups, the serum total protein content of the FSR group was increased （P< 0.05）, and the urea nitrogen content was reduced （P<0.05）. Compared with the SR group, the serum albumin content of the FSR group was increased significantly （P<0.05）. In conclusion, the addition of fermented soybean residues in the diet significantly improved the average daily gain of Hu sheep, reduced the feed cost, improved the apparent digestibility of DM, CP and NDF, and improved the meat quality and serum biochemical indexes. © 2022 Editorial Office of Acta Prataculturae Sinica. All rights reserved.     

Calorific Values of Grassland Plant Population and Functional Groups in the Agro-pastoral Ecotone of Inner Mongolia and Liaoning Province Border北大核心CSCD

Agro-pastoral ecotone is an important ecological barrier in China,and its ecological environment problems are becoming increasingly prominent. In this study,61 species of plants in 27 grassland plots in the agro-pastoral ecotone of Inner Mongolia and Liaoning border were collected for calorific value analysis under the random sampling condition. The changes of calorific value of plants in different types of functional groups were explored to provide scientific data and research support for energy fixation and rational use of grassland resources in the agro-pastoral ecotone. The results showed that:The average calorific value of 61 species was 17.14 KJ·g-1. Among them,Salsola collina had the lowest calorific value (12.82 KJ·g-1),the caloric value of Polygala tenuifolia was the highest (20.07 KJ·g-1),and the total calorific value was normal distribution. Comparing the caloric values of different life-type functional groups,the caloric value of annuals and biennials was significantly lower than perennial grasses and shrubs (P<0.05),which had no significant difference with sub-shrubs and perennial forbs. There was no significant difference among perennial grasses,shrubs,perennial weeds and semi-shrubs (P>0.05). There was no significant difference in caloric value between different water ecological functional groups (P>0.05). The plant caloric mean value of the Xero-mesophytes was slightly lower than other groups. There was no significant difference in calorific value among Liliaceae,Leguminosac,Gramineae,Compositae and Rosaceae,and the caloric value of Chenapodiaceae was significantly lower than other families (P<0.05). There was a significant positive correlation between plant calorific value and carbon content (P<0.05). © 2019 China Agricultural University. All rights reserved.     

Effects of Dietary Supplemented with Combined Yeast⁃Bacillus coagulans Fermentation Culture on Intestinal Morphology,Intestinal Permeability,Cecal Fermentation and Microflora of Rex Rabbits北大核心CSCD

This experiment was conducted to investigate the effects of dietary supplemented with combined yeast and Bacillus coagulans fermentation culture on intestinal morphology, intestinal permeability, cecal fer⁃ mentation and microflora of Rex rabbits. A total of 160 healthy Rex rabbits weaned at 35⁃day⁃old with similar body weight were randomly allocated to 4 groups with 8 replicates per group and 5 rabbits per replicate. Rex rabbits in the control group were fed a basal diet, while the others in experimental groups were fed experimental diets supplemented with 0.01%, 0.02% and 0.04% combined yeast and Bacillus coagulans fermentation cul⁃ ture based on the basal diet, respectively. The pretrial period lasted for 7 days and formal period lasted for 56 days. The results showed as follows: 1) the crypt depth of jejunum in the 0.02% and 0.04% added groups was significantly lower than that in the control group (P<0.05), the jejunum villus height / crypt depth ratio in the 0.02% added group was significantly higher than that in the control group (P < 0. 05), and the ileum villus height in the 0.04% added group was significantly higher than that in the control group (P<0.05) . 2) The ac⁃ tivity of diamine oxidase (DAO) in serum of 0.01% and 0.02% added groups was significantly lower than that in the control group (P<0.05), but there was no significant difference in the content of D⁃lactic acid (D⁃LA) in serum among all groups (P>0.05). 3) There were no significant differences in the pH of jejunum, ileum and cecum among all groups (P>0.05). There were no significant differences in the concentrations of acetic acid, propionic acid, butyric acid and total volatile fatty acid and the ratios of acetic acid, propionic acid and butyric acid in cecum among all groups (P>0.05). 4) Compared with the control group, the Simpson index of 0.02% and 0.04% added groups showed an increasing trend (0.05≤P<0.10). At the phylum level, the rela⁃ tive abundance of Verrucomicrobia showed a trend of decreasing first and then increasing with the combined yeast and Bacillus coagulans fermentation culture increasing (0.05≤P<0.10); the relative abundance of Te⁃ nericutes in the 0.02% added group was significantly higher than that in the 0.01% and 0.04% added groups (P<0.05), but there was no significant difference between the added groups and the control group (P>0.05). At the genus level, the relative abundance of Ruminococcaceae_UCG⁃014, Akkermansia, dgA⁃11_gut_group, Paramuribaculum and Subdoligranulum showed a trend of change with the combined yeast and Bacillus coagu⁃ lans fermentation culture increasing (0.05≤P<0.10). In summary, dietary supplemented with combined yeast and Bacillus coagulans fermentation culture can improve the intestinal morphology and reduce intestinal perme⁃ ability, but has no significant effects on the pH of jejunum, ileum and cecum and cecum fermentation, and can improve the microbial diversity of cecum of Rex rabbits. The recommended addition level is 0.02% to 0.04% based on the previous results of growth performance. © 2023 Chinese Journal of Clinical Research. All rights reserved.     

A comparison of average daily gain,apparent digestibilities,energy balance,rumen fermentation parameters,and serum metabolites between yaks(Bos grunniens) and Qaidam cattle(Bos taurus) consuming diets differing in energy level

Yaks (Bos grunniens),indigenous to the harsh Qinghai-Tibetan Plateau,are well adapted to the severe conditions,and graze natural pasture without supplements all year round.Qaidam cattle (Bos taurus),introduced to the Qinghai-Tibetan Plateau 1,700 years ago,are raised at a lower altitude than yaks,provided with shelter at night and offered supplements in winter.Based on their different backgrounds,we hypothesized that yaks have lower energy requirements for maintenance than cattle.To test this hy...     

Effects of the dietary nonfiber carbohydrate content on lactation performance,rumen fermentation,and nitrogen utilization in mid-lactation dairy cows receiving corn stover

Background: Corn stover(CS) is an abundant source of feed for livestock in China. However, it is low in nutritional value that we have been seeking technologies to improve. Previous studies show that non-fiber carbohydrate(NFC)might limit the utilization of a CS diet by lactating dairy cows. Thus, this study was conducted to investigate the lactation performance and rumen fermentation characteristics in lactating cows consuming CS with two contents of NFC compared to an alfalfa hay-containing diet. Twelve Holstein cows were used in a replicated 3 × 3 Latin square design with three dietary treatments:(1) low-NFC diet(NFC = 35.6%, L-NFC),(2) high-NFC diet(NFC = 40.1%,H-NFC), and(3) alfalfa hay diet(NFC = 38.9%, AH).Results: Intake of DM was lower for cows fed H-NFC compared to L-NFC and AH, while the milk yield was higher in AH than in H-NFC and L-NFC(P 0.01). The feed efficiency(milk yield/DM intake, 1.15 vs. 1.08, P 0.01) were greater for cows fed H-NFC than L-NFC. The contents of milk protein and lactose were not different among the groups(P 0.11), but milk fat content was higher for cows fed H-NFC and L-NFC compared to AH(P 0.01). The rumen ammonia nitrogen concentration and the concentrations of urea nitrogen in blood and milk were lower for cows fed H-NFC and AH compared to L-NFC(P 0.05). The concentrations of rumen propionate and total volatile fatty acids were different among groups(P 0.05) with higher concentration for cows fed AH compared to H-NFC and L-NFC, and acetate concentration tended to be different among groups(P = 0.06).Conclusions: From the results obtained in this study, it was inferred that the increased NFC content in a diet containing corn stover can improve the feed efficiency and benefit the nitrogen conversion.     

Effects of dietary neutral detergent fiber on muscle fiber type composition and meat quality characteristics of black Tibetan sheep北大核心CSCD

The effects of different neutral detergent fiber （NDF） diets on body size indexes，muscle fiber type and meat quality of Qinghai black Tibetan sheep were investigated. Forty healthy 2-month-old black Tibetan sheep with similar body weights ［（10.28±0.43 kg］ were randomly divided into 2 groups with 20 rams per group. They were fed diets with differing neutral detergent fiber （NDF） levels of 26.33% （group L） and 46.14% （group H）. Using enzyme-linked immunosorbent assay， ATPase histochemical stain and real-time PCR， the muscle fiber characteristics，gene expression of myosin heavy chains （MyHCs） and meat quality in Black Tibetan sheep were evaluated. Results were as follows：1） The tagma indexes in group H were significantly lower than those in group L （P<0.05）. 2） The number of type II a muscle fibers in group H was significantly more than in group L （P< 0.05），and the areas of type I and type II a muscle fibers in group H were also greater than in group L （P< 0.05）. 3） The mRNA expression levels of MyHC I and MyHC IIa in group L were lower than those in group H （P<0.05），but the mRNA expression levels of MyHC IIb and MyHC IIx exhibited an opposite movement （P< 0.05）. 4） Compared with group L，superoxide dismutase，glutathione peroxidase，catalase and total antioxidant capacity contents increased （P>0.05） in group H，while the malondialdehyde （MDA） content was significantly decreased with in group L. 5） The muscle shear force in Group L was higher than that in Group H （P<0.05），while the redness （a*） was lower than that in Group H （P>0.05）. In conclusion，compared with a low-NDF diet，the high-NDF diet effectively reduced the proportion of glycolic muscle fiber and also enhanced antioxidant capacity，improving the muscle quality of black Tibetan sheep. © 2022 Editorial Office of Acta Prataculturae Sinica. All rights reserved.