Research Progress of Effects of Maternal Supplementing Rumen-Protected Methionine during Transition Period on Growth and Development of Young Ruminant and Regulatory Mechanism北大核心CSCD

围产期是反刍动物重要的生理阶段,研究发现反刍动物围产期补饲过瘤胃蛋氨酸(RPM)不仅对母体具有显著的营养调控作用,对幼畜的生长发育、机体健康和产品品质等也有重要影响。因此,本文从RPM的营养调控功能,围产期补饲RPM调控母体、胎儿后期及幼龄阶段的影响及调控机制进行综述,以期进一步为反刍动物围产期营养调控研究提供理论依据。     

Effects of Compound Plant Nutrients on Rumen Fermentation Parameters,Rumen Microbiota and Fatty Acid Composition of Longissimus dorsi Muscle in Finishing Small Tail Han Sheep北大核心CSCD

This study was conducted to investigate the effects of compound p1ant nutrients (CPN) on rumen fermentation parameters, rumen microbiota and fatty acid composition of longissimus dorsi musc1e in finishing sma11 tai1 Han sheep. Sixteen 4-month-o1d finishing sma11 tai1 Han sheep with an initia1 body weight (BW) of (24.18±0.31) kg were random1y divided into two groups, name1y, with 8 rep1icates per group and 1 sheep per rep1icate. The sheep in the contro1 group were fed a basa1 diet, whereas the sheep of the contro1 group (CPN group) was fed the basa1 diet supp1ementation with 3‰ CPN. The experiment 1asted for 97 days after 7 days adaption. The resu1ts showed as fo11ows: compared with the contro1 group, 1) adding CPN decreased the concentration of ammonia nitrogen (NH3-N) (P<0.05); 2) CPN supp1ementation affected beta diversity of rumen microbiota; 3) the re1ative abundance of Acidobacteriota, Erysipe1otrichaceae_UCG-002, Lactobacillus, and Megasphaera were enhanced by adding CPN (P<0.05), whereas, the re1ative abundance of Bacteroidetes and Prevotella was 1ower (P<0.05); 4) the supp1ementation of CPN had no significant effect on fatty acid composition of longissimus dorsi musc1e of fattening sma11-tai1ed Han sheep (P>0.05); 5) the contents of tota1 MUFA, C18:1n9c, C14:1, C16:1, C18:2n6c, C18:3n3 and n-3PUFA in the longissimus dorsi musc1e were corre1ated with the re1ative abundance of Megasphaera, Erysipe1otrichaceae_UCG-002, Succiniclasticum and Ruminococcus (P<0.05). In conc1usion, CPN can regu1ate the rumen microbiota structure and reduce the rumen NH3-N concentration of fattening sma11-tai1ed Han sheep. In production practice, CPN can be used as a rumen eco1ogica1 regu1ator. © 2023 Authors. All rights reserved.     

Effects of Bacillus amylolyticus on Rumen Dry Matter Digestibility,Fermentation Parameters and Metabolites of Dairy Cows北大核心CSCD

This experiment was conducted to study the effects of Bacillus amylolyticus on rumen dry matter digestibility, fermentation parameters and metabolites of dairy cows. Experiment 1: six dairy cows with permanent fistula and had the similar parity (2 to 3 fetuses), body weight [(662 ±57) kg], lactation days [(160 ± 22) d] and milk yield [(36.1 ±3.8) kg / d], were randomly divided into 3 groups with 2 cows per group. Using 3 ×3 Latin square design, each group was extra fed 0 (control group), 5 ×109 and 5 ×1010 CFU / d Bacillus amylolyticus, the trial period was 3 periods, 13 days for each period, including 10 days for the pre-trial period and 3 days for the trial period. At the beginning of the trial period, the rumen dry matter digestibility of cows was measured by nylon bag method. Experiment 2: thirty dairy cows with similar parity [(2.5 ±0.3) fetuses], initial body weight [(559.2 ± 7. 4) kg], milk yield [(35. 2 ± 1. 5) kg / d] and lactation days [(99 ± 22) d] were randomly divided into three groups with 10 cows in each group. Cows in the 3 groups were extra fed with 0 (control group), 5 ×109 and 5 ×1010 CFU / d Bacillus amylolyticus, respectively. The pre-trial period was 10 days and the trial period was 42 days. The rumen fluid was collected on the last day of the trial period, and the rumen fermentation parameters and metabolites were determined. The results showed as follows: compared with the control group, 1) supplementary feeding of 5 × 1010 CFU / d Bacillus amylolyticus could significantly improve the rumen dry matter digestibility of dairy cows at 12, 24, 36, 48 and 72 h (P <0.05), supplementary feeding of 5 ×109 CFU / d Bacillus amylolyticus could significantly improve the rumen dry matter digestibility of dairy cows at 36 and 48 h (P <0.05); 2) supplementary feeding of 5 ×109 CFU / d Bacillus amylolyticus could significantly increase the contents of isobutyric acid, butyric acid, isovaleric acid, valeric acid, total volatile fatty acid and microbial protein in the rumen of dairy cows (P < 0. 05), supplementary feeding of 5 × 1010 CFU / d Bacillus amylolyticus could significantly increase the contents of isobutyric acid and isovaleric acid in the rumen of dairy cows and significantly reduce the rumen acetic acid / propionic acid (P < 0. 05), supplementary feeding of 5 ×109 and 5 ×1010 Bacillus amylolyticus had no effects on rumen pH and ammonia nitrogen content (P >0.05); 3) eleven metabolic pathways related to differential metabolites were detected, and ascorbic acid and alginate metabolism were significantly enriched (P < 0. 05) . In conclusion, Bacillus amylolyticus can increase the rumen dry matter digestibility, and improve the rumen fermentation function of dairy cows by affecting the content of rumen metabolites. By comprehensive analysis, supplementary feeding of 5 × 109 CFU / d Bacillus amylolyticus can achieve better effect. © 2023 Authors. All rights reserved.     

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 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.     

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.     

Effects of dietary γ-aminobutyric acid supplementation on antioxidant status,blood hormones and meat quality in growing-finishing pigs undergoing transport stress

γ-Aminobutyric acid (GABA) is a natural nonprotein amino acid distributed in animals, plants and microbes. GABA is an inhibiting neurotransmitter which takes great effect in mammalian central nervous system. We carried out the research to study the influence of GABA on blood hormone concentrations, antioxidant status and meat quality in fattening pigs after transportation. The 72 pigs with a starting weight of approximately 32.67 ± 0.62 kg were randomly allocated to 2 groups based on dietary treatments, containing 6 replicates with 6 pigs in each. The pigs were fed dietary supplementation of GABA (0 or 30 mg/kg of diets) for 74 days. Twelve pigs were randomly selected from each group and assigned to the either 1 hr of transport (T group) or no transport (N group), resulting in two-factor factorial design. Compared to the control, GABA supplementation increased average daily gain (ADG) (p < .01) and decreased feed–gain ratio (F/G) (p < .05). The pH_45 min was lower and drip loss was greater in the longissimus muscles (LM) of post-slaughter of transported pigs (p < .05). The pH_45 min of 0/T group (group with 0 mg/kg GABA and transport) was significantly lower than the pH_45 min of the 30/T group (diet × transport; p < .05). GABA supplementation significantly increased serum glutathione peroxidase (GSH-Px) concentration (p < .05) before transportation. Following transport, pigs fed GABA had decreased concentrations of serum malonaldehyde (MDA), adrenal cortical hormone and cortisol (p < .05). The results indicate that feeding GABA significantly increased the growth performance of growing-finishing pigs. The transportation model negatively impacted meat quality, antioxidant indexes and hormone parameters, but dietary supplementation of GABA could suppress the rise of drip loss of LM, ACTH and COR and suppress the drop of pH_45 min of LM after transportation stress in growing-finishing pigs. Feeding GABA alleviated transportation stress in pigs.     

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.     

Screening of antifreeze-thawed lactic acid bacteria and their effects on oat silage fermentation quality and aerobic stability北大核心CSCD

The effects of freeze-thaw conditions on the fermentation quality and aerobic stability of oat silage were investigated. Four strains of freeze-thaw-resistant lactic acid bacteria（LAB）with rapid growth and efficient acid production were screened from 437 strains,which had been isolated from the Qinghai-Tibetan Plateau. Based on physiological and biochemical characteristics and 16S rRNA gene sequence alignment,the four strains were identified as Lactobacillus plantarum 157（LP157）,L. plantarum 160（LP160）,Lactobacillus brevis 248（LB248）,and Lactobacillus pentosus 260（LPE260）. In order to investigate their effects on the fermentation quality,nutrient composition,microbial counts and aerobic stability of oat silage under freeze-thaw conditions,seven treatments were tested as follows：1）LP157;2）LP160;3）LB248;4）LPE260;5）LP160+Lactobacillus rhamnosus 753 mixture （MIX）;6）A commercial bacterial silage additive（COM）;7）The same amount of sterilized distilled water（CK）. All treatments were ensiled for 60 days at a constant temperature of 20 ℃ and under a 20 ℃/-5 ℃ regime alternating every 12 h（freeze-thaw）. LP inoculation improved silage quality：The pH and dry matter loss in silages inoculated with LP157,LP160,LB248 and LPE260 were significantly lower than CK（P<0. 05）and lactic acid and acetic acid contents were significantly higher than CK（P<0. 05）,and the growth of spoilage micro-organisms such as coliform bacteria,yeast and mold were inhibited,both with fermentation at constant 20 ℃ and under freeze-thaw conditions. After aerobic exposure for 5 days,the pH and NH3-N of silages treated with LP157,LP160,LB248 and LPE260 were significantly（P<0. 05） lower than CK,MIX and COM. The aerobic stability of oat silage was improved,especially when inoculated with LP160（70 h vs. CK 11 h）. The results show that the four screened strains can be used as effective LAB inoculants for silage preparation in the freeze-thaw environment of the Qinghai-Tibetan Plateau. © 2022 Editorial Office of Acta Prataculturae Sinica. All rights reserved.     

Effects of gibberellin and its inhibitors on growth and gene expression in Poa pratensis北大核心CSCD

研究了不同浓度的赤霉素及其抑制剂烯效唑和多效唑对草地早熟禾生长及赤霉素相关基因表达的影响,为外源生长调节剂在草坪养护管理中的高效利用提供理论依据。以1/2 Hogland营养液培养的草地早熟禾为材料,随机分成7组,分别施用不同浓度的赤霉素、烯效唑、多效唑,测定根及叶片的生长量、叶绿体分布、叶绿素含量以及赤霉素相关基因的表达量。结果显示：与对照比较,外源烯效唑和多效唑均显著抑制草地早熟禾的伸长生长以及干/鲜重,但提高了根冠比、叶绿素a、叶绿素b及类胡萝卜素含量（P<0.05）;增加了叶肉细胞层数,使叶绿体充满在叶片上下表皮之间的叶肉细胞中;赤霉素合成代谢途径关键酶基因PpKAO、PpKS1、PpGA₃ox、PpGA₂ox表达量显著下调,赤霉素信号转导受体蛋白基因PpGID1显著上调（P<0.05）。外源赤霉素对草地早熟禾的伸长生长具有促进作用,但降低了根、叶的干/鲜重,提高根冠比,显著提高了赤霉素分解基因PpGA₂ox表达量（P<0.05）。总之,烯效唑、多效唑对草地早熟禾生长发育及基因表达的调控作用与赤霉素相反,但无明显浓度效应;在草坪修剪后立即喷施1000倍的烯效唑或多效唑,对减少用工成本,增加草坪观赏性、提高园林绿化中的草坪草管护水平具有重要意义。     

日粮粗蛋白质水平对育肥湖羊瘤胃微生物组成和发酵参数的影响

为研究日粮粗蛋白质水平(crude protein, CP)对育肥湖羊瘤胃微生物、pH及VFA含量的影响,选取54只4月龄[(32.25±2.50) kg]湖羊公羔,采用完全随机分组设计,将试验羊分为3个处理组,每个处理组18个重复,每个重复1只羊,3个处理组日粮CP水平分别为11.5%、14.0%、16.5%,试验期共70 d,包括7 d预试期,63 d正试期。试验期结束后,每组选择10只试验羊进行屠宰,测定屠宰性能并采集瘤胃内容物,用于瘤胃微生物DNA提取。结果表明:1)不同CP处理组对宰前活重、胴体重、屠宰率、瘤胃总重、瘤胃组织重及尾脂重无显著影响(P> 0.05)。2) 11.5%CP组瘤胃液氨态氮显著低于14.0%CP及16.5%CP组(P <0.001),但14.0%CP组与16.5%CP组无显著差异(P>0.05)。瘤胃液p H随日粮蛋白水平的增加有增加的趋势(P <0.1)。3)总挥发性脂肪酸(total volatile fatty acids, TVFA)浓度不受日粮中CP水平的影响(P> 0.05),其中乙酸、丙酸、异丁酸、丁酸、戊酸...     

日粮补充异丁酸对犊牛生长性能、瘤胃发酵和纤维分解菌菌群的影响

为探索异丁酸对犊牛生长性能、瘤胃发酵、纤维分解菌菌群和酶活性的影响,试验选用15日龄荷斯坦犊牛36头,随机分成4组,对照组、低水平异丁酸组(LIB)、中水平异丁酸组(MIB)和高水平异丁酸组(HIB)分别饲喂异丁酸0、3、6和9g·d^-1,预饲15d,分别于60日龄(断奶)和90日龄测定体重和采集瘤胃液进行分析。结果表明,MIB组和HIB组犊牛干物质采食量、日增重和经济效益显著高于对照组(P<0.05)。90日龄时HIB组犊牛瘤胃pH值显著低于对照组和LIB组(P<0.05)。MIB和HIB组瘤胃总挥发性脂肪酸和乙酸浓度显著高于对照组和LIB组(P<0.05);MIB和HIB组犊牛60日龄时瘤胃乙酸/丙酸显著高于对照组(P<0.05),90日龄时显著高于对照组和LIB组(P<0.05)。60和90日龄时MIB和HIB组瘤胃异丁酸均显著高于对照组(P<0.05)。60日龄时MIB和HIB组木聚糖酶和α-淀粉酶显著高于对照组(P<0.05),MIB和HIB组纤维二糖酶、果胶酶、溶纤维丁酸弧菌、黄色瘤胃球菌和产琥珀酸丝状杆菌显著高于对照组和LIB组(P<0.05);90日龄时MIB和HIB组各种瘤胃酶活力和纤维分解菌均显著高于对照组和LIB组(P<0.05)。结果显示,日粮补充异丁酸促进了犊牛瘤胃纤维素分解菌的生长,提高了纤维素分解酶的活性,进而促进了犊牛瘤胃发酵和生长发育。由于MIB与HIB之间各指标差异不显著,兼顾经济效益,在本试验条件下异丁酸的最佳添加量为6.0g·d^-1。     

羔羊日粮精粗比对其肉及脂肪组织中脂肪酸组成的影响

为了研究不同精粗比日粮对广河羊羔肉品质的影响,在广河县羔羊肉生产区,选择不同精粗比饲喂的6月龄健康陶寒杂交(陶赛特羊♂×小尾寒羊♀)断奶去势公羔各3只进行屠宰,取股二头肌、背最长肌、肱二头肌3个部位肌肉和肾周脂肪、皮下脂肪、尾部脂肪3个部位脂肪,用气象色谱法分析其脂肪酸的种类及含量。结果表明,在所有组织中均检测出38种脂肪酸,其中饱和脂肪酸17种,不饱和脂肪酸21种。脂肪组织中饲喂低精粗比日粮的亚油酸(C18∶2n6c)、α-亚麻酸(C18∶3n3)、饱和脂肪酸(SFA)、多不饱和脂肪酸(PUFA)及其与饱和脂肪酸比值(P/S)、n3系多不饱和脂肪酸和n6系多不饱和脂肪酸均显著高于饲喂高精粗比日粮(P<0.05);饲喂低精粗比日粮的所有组织中花生四烯酸(C20∶4)的含量显著高于饲喂高精粗比日粮(P<0.05);与饲喂高精粗比日粮的羊羔肉相比,饲喂低精粗比日粮既节省了生产成本又明显改善和提高了羊羔肉中脂肪酸的营养价值。     

营养水平对荣昌猪肌内脂肪、脂肪酸含量的影响研究

试验选用84头10 kg左右荣昌阉公猪,随机分成2组,每组6个重复,每个重复7头猪,在参照中国瘦肉型猪饲养标准(高营养水平组)、荣昌猪(GB 7223—1987)饲养标准(低营养水平组)配制的2种日粮饲喂条件下,研究日粮营养水平对生长肥育期荣昌阉公猪肌内脂肪、脂肪酸含量及组成的影响。结果表明:本试验条件下,营养水平对生长育肥阶段荣昌猪肌内脂肪含量无显著影响;高营养水平组显著提高荣昌猪35 kg时硬脂酸含量(P0.05)和20 kg时亚麻酸含量(P0.05);荣昌猪的饱和脂肪酸、不饱和脂肪酸和必需脂肪酸含量,高低营养水平组在各个体重阶段差异均不显著(P0.05)。     

Effects of concentrate‐to‐forage ratios and 2‐methylbutyrate supplementation on ruminal fermentation,bacteria abundance and urinary excretion of purine derivatives in Chinese Simmental steers

This study evaluated the effects of dietary concentrate levels and 2‐methylbutyrate (2MB ) supplementation on performance, ruminal fermentation, bacteria abundance, microbial enzyme activity and urinary excretion of purine derivatives (PD ) in steers. Eight ruminally cannulated Simmental steers (12 months of age; 389 ± 3.7 kg of body weight) were used in a replicated 4 × 4 Latin square design with a 2 × 2 factorial arrangement. Moderate‐concentrate (400 g/kg diet [MC ]) or high‐concentrate (600 g/kg diet [HC ]) diets were fed with or without 2MB (0 g/day [2MB ?] or 15.0 g/day [2MB +]). Dry matter intake and average daily gain increased, but feed conversion ratio decreased with the HC diet or 2MB supplementation. Ruminal pH decreased, but total volatile fatty acid increased with the HC diet or 2MB supplementation. Molar proportion of acetate and acetate‐to‐propionate ratio decreased with the HC diet, but increased with 2MB supplementation. Propionate molar proportion and ruminal NH ₃‐N content increased with the HC diet, but decreased with 2MB supplementation. Neutral detergent fibre degradability decreased with the HC diet, but increased with 2MB supplementation. Crude protein degradability increased with the HC diet or 2MB supplementation. Abundance of Ruminococcus albus , Ruminococcus flavefaciens , Fibrobacter succinogenes and Bufyrivibrio fibrisolvens as well as activities of carboxymethyl cellulase, cellobiase, xylanase and pectinase decreased with the HC diet, but increased with 2MB supplementation. However, abundance of Prevotella ruminicola and Ruminobacter amylophilus as well as activities of α‐amylase and protease increased with the HC diet or 2MB supplementation. Total PD excretion also increased with the HC diet or 2MB supplementation. The results suggested that growth performance, ruminal fermentation, CP degradability and total PD excretion increased with increasing dietary concentrate level from 40% to 60% or 2MB supplementation. The observed diet × 2MB interaction indicated that supplementation of 2MB was more efficacious for improving growth performance, ruminal fermentation and total PD excretion with promoted ruminal bacteria abundance and enzyme activity in the MC diet than in the HC diet.     

The effects of dietary medium-chain fatty acids on ruminal methanogenesis and fermentation in vitro and in vivo: A meta-analysis

The efficacy of methane (CH₄) suppression using medium-chain fatty acids (MCFA) remains inconclusive, despite a number of studies on this topic are available. We thus carried out a meta-analysis to integrate the published data on different concentrations and types of MCFA such as lauric acid and myristic acid, which investigated ruminal methanogenesis and fermentation in in vitro and in vivo experiments. In vitro MCFA sources were classified either as pure MCFA (lauric acid, myristic acid and their combinations) or as natural MCFA-rich oils (canola oil enriched with lauric acids, coconut oil, krabok oil and palm kernel oil). The MCFA sources used in the in vivo studies were coconut oil, lauric acid, myristic acid and the combination of lauric and myristic acids. A total of 41 studies (20 in vitro and 21 in vivo studies) were compiled in our database, which included the data on CH₄ emission, digestibility, ruminal fermentation products and microbial populations. The results showed that the amount of CH₄ production per unit of digested organic matter decreased linearly under in vitro conditions (p < .01) and tended to decrease quadratically under in vivo conditions (p < .07) with increasing doses of MCFA. Populations of protozoa (p < .01) in both in vitro and in vivo responded negatively in a linear manner, whereas Archaea population diminished quadratically (p = .04) only in the in vitro conditions with increasing doses of MCFA. Increasing dietary MCFA concentrations also reduced the fibre digestibility linearly (p < .05) in both in vitro and in vivo conditions. CH₄ production for different sources of MCFA decreased in following order: coconut oil > lauric acid > myristic acid > mixed lauric and myristic acids > palm kernel oil > canola oil enriched with lauric acids > krabok oil. It can be concluded that the effect of MCFA on ruminal methanogenesis depends on the amount and type of MCFA.     

Effects of fermented Yupingfeng on intramuscular fatty acids and ruminal microbiota in Qingyuan black goats

Our previous work has demonstrated that Yupingfeng, a Chinese herb medicine, considered as prebiotic showed beneficial properties in poultry health and disease prevention and regulated intestinal microbiota. The effects of Yupingfeng on fatty acids related to meat flavor and ruminal microbiota are not yet known in Qingyuan black goat. In this study, we supplemented fermented (FYP) and unfermented (UYP) Yupingfeng in different combinations to 90 goats. Compared with the normal control group, FYP and UYP significantly increased the concentration of palmitic acid, octadecanoic acid, and arachidonate acid (related to meat flavor) in the longissimus dorsi muscle (p < .05). In addition, the significant upregulation of peroxisome proliferator-activated receptor gamma (PPARγ) and fatty acid translocase (CD36) was observed in the FYP and UYP groups (p < .05). In addition, Firmicutes and Bacteroidetes were the most abundance in goat rumen. At the genus level, FYP and UYP significantly increased Ruminococcus related to fiber degradation, and Alistipes related to short-chain fatty acids production. In summary, Yupingfeng could improve fatty acids of goat meat, which is probably triggered by the increase of PPARγ and CD36, and microbial activity. Besides, FYP showed more beneficial effects than UYP, with increased flavor fatty acids and beneficial microbes.     

The relationships between odd‐ and branched‐chain fatty acids to ruminal fermentation parameters and bacterial populations with different dietary ratios of forage and concentrate

The objectives of this study were to investigate the effect of different dietary ratios of forage and concentrate (F:C) on ruminal odd‐ and branched‐chain fatty acids (OBCFAs) contents and to evaluate the relationships between OBCFA and ruminal fermentation parameters as well as bacterial populations tested by real‐time PCR technique. The experimental design was a 3 × 3 Latin square. Three rumen‐fistulated dry Holstein cows were fed three rations with different dietary F:C ratios (F:C; 30:70, 50:50 and 70:30). The rumen samples were collected every two hours (0600, 0800, 1000, 1200, 1400, 1600, 1800, 2000, 2200, 2400, 0200 and 0400 h) over three consecutive days in each sampling period. The results showed that rumen OBCFA profiles are significantly (p < 0.05) affected by the dietary F:C ratios. The concentrations of C11:0, C13:0, iso‐C15:0, iso‐C16:0, iso‐C17:0 and C17:0 were higher in the cows fed dietary F:C ratio of 70:30 than those fed with other two rations. However, the concentrations of anteiso‐C15:0, C15:0 and total OBCFA were on the lowest level in the high forage diet. Correlation and regression analysis showed that ruminal OBCFAs had strong relationships with ruminal fermentation parameters and bacterial populations. In particular, the iso‐fatty acids had potential power to predict butyrate and isoacids metabolized in the rumen, whereas the fatty acids with 17 carbon atoms correlated with ruminal NH₃‐N content. The OBCFA contents have different relationships with fibrolytic and starch bacteria in the rumen. C17:0 and its isomers might be used to predict populations of fibrolytic bacteria.     

Effects of increasing amount of dietary Prosopis laevigata pods on performance,meat quality and fatty acid profile in growing lambs

A study with finishing lambs assessed the effect of dietary inclusion of Prosopis laevigata pods (PLPs) on performance, carcass characteristics, meat traits and fatty acid profile of subcutaneous fat. Twenty‐one Rambouillet lambs (27.0 ± 3.0 kg BW) were assigned to one of three experimental diets with 0, 150 and 300 g PLP/kg DM. Evaluation of growth performance lasted 49 days. The experimental design was completely randomized and analysed with a mixed model. Lambs fed diets with 0, 150 and 300 g PLP had similar growth performance. Lambs fed diets with 300 g PLP/kg DM had better (p < 0.05) carcass yield and classification, less (p < 0.05) fat deposition and lower lightness (L*) value (p < 0.05) in meat than lambs fed diets with 0 and 150 g PLP/kg DM. Saturated fatty acids (palmitic and stearic) decreased (p < 0.05) and unsaturated fatty acids (oleic and linoleic) increased (p < 0.05) in subcutaneous fat of lambs fed diets with 150 and 300 g pods as compared with lambs not fed PLP. Prosopis laevigata pods are a safe feedstuff that can replace a third of conventional ingredients and reduce feed costs in growing lambs. Addition of PLP reduced (p < 0.05) total feed cost by 21%.     

Effects of rumen‐protected folic acid and dietary protein level on growth performance,ruminal fermentation,nutrient digestibility and hepatic gene expression of dairy calves

This study evaluated the effects of rumen‐protected folic acid (RPFA) supplementation and dietary protein level on growth performance, ruminal fermentation, nutrient digestibility and hepatic gene expression in calves. Forty Holstein male calves (161 ± 5.7 days of age and 192 ± 5.4 kg of body weight) were assigned to one of four groups in a randomized experimental design with a 2 × 2 factorial arrangement. Moderate crude protein (130.1 g CP/kg [MCP] or high crude protein (150.2 g CP/kg [HCP]) diets were fed without (RPFA?) or with 3.6 mg FA (RPFA+) as RPFA per kg dietary dry matter (DM). Calves were fed a total mixed ration with a corn silage to concentrate ratio of 50:50 on a DM basis. The CP×RPFA interaction was not significant for any of the studied variables. The unchanged DM intake, higher average daily gain and lower feed conversion ratio were observed for HCP or RPFA+. Ruminal pH was lower, and total volatile fatty acids (VFA) concentration was higher for HCP or RPFA+. Acetate proportion was higher, and propionate proportion was lower for HCP or RPFA+. As a result, the higher acetate to propionate ratio was observed. Ruminal ammonia N was higher for HCP, but was lower with RPFA supplementation. The higher digestibility of DM, OM, CP and NDF was observed. Blood glucose and insulin were unchanged, but albumin, total protein, GH and IGF‐1 were higher. Similarly, the higher hepatic expression of GH, IGF‐1, GHR, IGF‐1R, PI3K, mTOR and P70S6K was observed for HCP or RPFA+. The results indicated that increasing dietary CP content or supplementation with RPFA promoted growth performance of calves by improving nutrient utilization and up‐regulating hepatic expression of gene related to protein synthesis.