Comparison of feed intake,digestion and rumen function among domestic ruminant species grazing in upland vegetation communities

This study aimed to compare feed intake, digestion, rumen fermentation parameters and bacterial community of 5 beef cows, 12 crossed ewes and 12 goats grazing together in spring–early summer on heather–gorse vegetation communities with an adjacent area of improved pasture. Organic matter intake (OMI) and digestibility (OMD) were estimated using alkane markers. Ruminal fluid samples were collected for measuring fermentation parameters, and studying the bacterial community using terminal restriction fragment length polymorphism (T‐RFLP). Spot samples of urine were taken to determine purine derivative (PD) and creatinine concentrations to estimate microbial protein synthesis in the rumen. Herbaceous species were the main dietary component in all animal species. Cattle had higher (p < 0.05) daily OMI (g/kg LW^0.75) and OMD, whereas sheep and goats showed similar values. The highest ammonia concentration was observed in sheep. Total VFA, acetate and butyrate concentrations were not influenced by animal species, while propionate concentrations in goats were 1.8 times lower (p < 0.05) than in sheep. Acetate:propionate ratio was greater (p < 0.05) in goats, whereas cattle excreted more allantoin (p < 0.05). Estimated supply of microbial N was higher in cows (p < 0.01), whereas the efficiency of microbial protein synthesis was lower (p < 0.01) in this animal species. Hierarchical clustering analysis indicated a clear effect of animal species on rumen bacterial structure. Differences among animal species were also observed in the relative frequency of several T‐RFs. Certain T‐RFs compatible with Lachnospiraceae, Proteobacteria and Clostridiales species were not found in goats, while these animals showed high relative frequencies of some fragments compatible with the Ruminococcaceae family that were not detected in sheep and cattle. Results suggest a close relationship between animals’ grazing behaviour and rumen bacterial structure and its function. Goats seem to show a greater specialization of their microbial populations to deal with the greater fibrous and tannin content of their diet.     

Influences of dietary regimens on microbial content in gastrointestinal tracts of meat goats

This experiment was conducted to evaluate the effects of dietary treatments on microbial loads and pH of gastrointestinal tract contents in meat goats, as well as the concentration of volatile fatty acid (VFA) in the rumen. Crossbred (Boer x Spanish) goats (n = 36; BW = 17.7 kg) were assigned randomly to one of three experimental diets (n = 12/diet or 3 pens/treatment) for 90 days:alfalfa (Medicago sativa) hay alone (AH-diet); 18% CP concentrate alone (C-diet); or, a combined diet (AHC-diet), consisting of the AH-diet for the first 45 days, followed by 45 days of the C-diet. After evisceration, pH values of rumen liquor and colon digesta were immediately measured from each animal, as well as aseptically collected rumen liquor and rectal samples to determine the microbial loads. Collected rumen liquor was also prepared for volatile fatty acid (VFA) contents. Feeding meat goats with alfalfa hay alone had higher (P < 0.05) rumen (7.17) and colon (7.10) pH compared with those fed either the concentrate alone or combined-diet. Although the acetate content was high in the AH-fed group (66.3 mM) compared to the AHC-diet group (34.6 mM), no significant differences were found in the total VFA contents in rumen liquor among the goats fed three different dietary regimens. Total plate counts were not significantly different among goats fed the experimental diets in the rumen or rectal samples. Escherichia coli counts in the rectal samples were lower (P < 0.05) in the AH-diet group (6.43 log₁₀ CFU/g) compared with the C-diet (8.21 log₁₀ CFU/g) or AHC-diet (8.40 log₁₀ CFU/g) groups. However, no significant differences were found in the E. coli counts of rumen samples from goats fed the experimental diets. The mean (± SEM) rumen E. coli counts were 1.38, 1.65, and 2.51 ± 0.560 log₁₀ CFU/g in the AH-, C-, and AHC-diet groups, respectively. The results indicate that feeding hay alone may decrease the fecal shedding of E. coli in meat goats with increasing the rumen and colon pH.     

Elevated cyclin D1 expression is governed by plasma IGF‐1 through Ras/Raf/MEK/ERK pathway in rumen epithelium of goats supplying a high metabolizable energy diet

The objective of this study was to explore the underlying mechanism of insulin‐like growth factor 1 (IGF‐1)–caused cell proliferation of rumen epithelium in goats fed a high metabolizable energy (ME) diet. In this study, young goats were fed either a low ME [LL, n = 9, ME: 0.57 MJ/kg^0.75/day] or high ME [HL, n = 9, ME: 1.00 MJ/(kg^0.75/day)] diet for 42 day. The time duration of G₁‐phase was shortened as a result of enhanced expression of cyclin D1 mRNA in the HL group (p < 0.05). It was suggested that a high ME diet promoted cell transition from G₀/G₁ to S‐phase via cyclin D1. The level of phosphorylation of ERK was higher in HL than LL group (p < 0.05). In cell culture, the ERK was phosphorylated by IGF‐1 treatment. The proliferative effects of insulin‐like growth factor 1 (IGF‐1, 25 ng/ml) on [³H] thymidine (TdR) incorporation into DNA and on cyclin D1 protein expression of rumen epithelial cells were inhibited by PPP (the inhibitor of type 1 IGF receptor) (p < 0.05) and ERK inhibitor (p < 0.05) in vitro. Thus, IGF‐1 up‐regulated cyclin D1 expression and accelerated G₁‐phase progression in the cell cycle through Ras/Raf/MEK/ERK pathway in rumen epithelium of goats.     

Effect of inclusion of HMBi in the ration of goats on feed intake,nutrient digestibility,rumen bacteria community and blood serum parameters

The objective of this experiment was to test the effect of supplementation of analogues of methionine 2-hydroxy-4-methylthio butanoic acid isopropyl ester (HMBi) on growth, digestibility, antioxidant index, abundance and composition of rumen bacterial community in Xiangdong Black Goats. Thirty-six growing Xiangdong Black Goats were divided into four groups in such a way that each group had three replicate and each replicate had three animals. Experimental groups were assigned four levels of HMBi in basal diet: 0% HMBi (on dietary DM basis); 0.05% HMBi; 0.10% HMBi and 0.20% HMBi. Goats fed 0.10% HMBi in basal diet had higher average daily weight gain (p < .05). Goats fed 0.05% HMBi had higher apparent digestibility of gross energy (p < .01). The group 0% HMBi supplementation had a higher level of superoxide dismutase and malondialdehyde (p < .01). The goats fed 0.20% HMBi in basal diet had a higher level of insulin and leptin (p < .01) than 0% HMBi supplementation goats. 16S rRNA high-throughput sequencing analysis revealed similarities in the community composition, species diversity and relative abundance of dominant bacteria at the phylum and genus levels among the four groups. In conclusion, HMBi supplementation has no negative effect on apparent digestibility, antioxidant index and the ruminal bacteria composition. Therefore, 0.10% supplementation of HMBi is recommended in the diet of goats to improve the growth performance.     

Effects of dietary Greek oregano (Origanum vulgare ssp. hirtum) supplementation on rumen fermentation,enzyme profile and microbial communities in goats

This study was conducted to examine in vivo long‐term effects of dietary dried oregano (Origanum vulgare ssp. hirtum) whole plant on rumen fermentation, enzyme profile and microbial communities. For this purpose, eight healthy, adult, non‐lactating Alpine goats were kept in tie stalls equipped for individual feeding and randomly divided into two homogeneous groups: one fed 0.6 kg of a concentrate mixture and 0.6 kg of wheat straw without any supplementation and served as control group (CON) while the other group (OR) fed the same diet of CON but supplemented with 20 g of dried oregano plants (OPs) to provide daily dosage of 1 ml of essential oil (EO) per animal. The experimental period lasted 69 days and individual rumen fluid samples were obtained every 2 weeks at 0 and 4 hr after feeding. The results showed that dietary supplementation with OPs increased the protease activity (p < .001) and ammonia concentration (p < .05) in the rumen. Among the studied microbial populations, Peptostreptococcus anaerobius (p = .028) and Clostridium sticklandii (p < .001) were found to be the most sensitive to oregano at the current dosage. Furthermore, the total methanogen population significantly decreased (p < .05). It is concluded that a long‐term dietary administration of OPs can suppress specific rumen micro‐organisms and modify rumen fermentation favourably at least by means of suppressing methanogens.     

Influence of vitamin E on organic matter fermentation,ruminal protein and fatty acid metabolism,protozoa concentrations and transfer of fatty acids

Vitamin E (Vit. E) is discussed to influence ruminal biohydrogenation. The objective of this study was to investigate the influence of a Vit. E supplementation on rumen fermentation characteristics, ruminal microbial protein synthesis as well as ruminal organic matter fermentation. Furthermore, we aimed to investigate the influence of Vit. E supplementation on short‐chain fatty acids (SCFA) and protozoa concentrations in the rumen and, in addition, on transfer rates of middle‐chain and long‐chain fatty acids into the duodenum in lactating dairy cows. Eight rumen and duodenum fistulated German Holstein cows were assigned to either a group receiving 2,327 IU/d Vit. E (138.6 IU/kg DM DL‐α‐tocopherylacetate; n = 4) or a control group (23.1 IU/kg DM; n = 4). Neither ruminal protein synthesis nor organic matter fermentation was influenced by treatment. Vit. E did not act on the concentrations of short‐chain fatty acids and protozoa in rumen fluid. Duodenal flow of C13:0 (1.3 versus 0.2 g/d, p = 0.014) and iso‐C14:0 (1.0 versus 0.5 g/d, p = 0.050) was higher in the Vit. E group. We observed a trend for higher duodenal flows for C12:0 (1.6 versus 0.9 g/d, p = 0.095) and anteiso‐C15:0 (12.2 versus 8.9 g/d, p = 0.084). Transfer rate of C12:0 tended to be higher in the Vit. E group (125.61 versus 73.96, p = 0.082). No other transfer rates were affected by treatment. Further studies are necessary to investigate the influence of Vit. E on rumen microbiota and their fatty acid production as well as on the impact of different doses of Vit. E supplementation on variables of protein synthesis efficiency.     

The effect of dietary Chlorella vulgaris supplementation on micro‐organism community,enzyme activities and fatty acid profile in the rumen liquid of goats

Microalgae might be considered as an alternative source of fat and/or protein for ruminant's diets. However, changes in populations of ruminal micro‐organisms associated with biohydrogenation process, methane and ammonia production in response to microalgae dietary supplementation have not been well characterized. Thus, 16 cross‐bred goats were divided into two groups. Each goat of both groups was fed individually with alfalfa hay and concentrates separately. The concentrates of the control group had no microalgae while those of the treated group were supplemented with 10 g lyophilized Chlorella vulgaris/kg concentrate (chlor). On the 30th experimental day, samples of rumen fluid were collected for microbial DNA extraction, fatty acid profile and enzyme activity analyses. The results showed that the chlor diet compared with the control increased significantly the populations of Methanosphaera stadtmanae, Methanobrevibacter ruminantium and Methanogens bacteria and protozoa in the rumen of goats. A significant reduction in the cellulase activity and in the abundance of Ruminococcus albus, and a significant increase in the protease activity and in the abundance of Clostridium sticklandii in the rumen liquid of goats fed with the chlor diet, compared with the control, were found. Chlorella vulgaris supplementation promoted the formation of trans C_18:1, trans‐11 C_18:1 and monounsaturated fatty acids (MUFA), while the proportions of C_18:0 and long‐chain fatty acids (LCFA) reduced significantly in the rumen liquid of goats. This shift in ruminal biohydrogenation pathway was accompanied by a significant increase in Butyrivibrio fibrisolvens trans C_18:1‐producing bacteria. In conclusion, the supplementation of diets with microalgae needs further investigation because it enhances the populations of methane‐producing bacteria and protozoa.     

Low ambient temperature elevates plasma triiodothyronine concentrations while reducing digesta mean retention time and methane yield in sheep

Ruminant methane yield (MY) is positively correlated with mean retention time (MRT) of digesta. The hormone triiodothyronine (T₃), which is negatively correlated with ambient temperature, is known to influence MRT. It was hypothesised that exposing sheep to low ambient temperatures would increase plasma T₃ concentration and decrease MRT of digesta within the rumen of sheep, resulting in a reduction of MY. To test this hypothesis, six Merino sheep were exposed to two different ambient temperatures (cold treatment, 9 ± 1 °C; warm control 26 ± 1 °C). The effects on MY, digesta MRT, plasma T₃ concentration, CO₂ production, DM intake, DM digestibility, change in body weight (BW), rumen volatile fatty acid (VFA) concentrations, estimated microbial protein output, protozoa abundance, wool growth, water intake, urine output and rectal temperature were studied. Cold treatment resulted in a reduction in MY (p < 0.01); digesta MRT in rumen (p < 0.01), hindgut (p = 0.01) and total digestive tract (p < 0.01); protozoa abundance (p < 0.05); and water intake (p < 0.001). Exposure to cold temperature increased plasma T₃ concentration (p < 0.05), CO₂ production (p = 0.01), total VFA concentrations (p = 0.03) and estimated microbial output from the rumen (p = 0.03). The rate of wool growth increased (p < 0.01) due to cold treatment, but DM intake, DM digestibility and BW change were not affected. The results suggest that exposure of sheep to cold ambient temperatures reduces digesta retention time in the gastrointestinal tract, leading to a reduction in enteric methane yield. Further research is warranted to determine whether T₃ could be used as an indirect selection tool for genetic selection of low enteric methane‐producing ruminants.     

Effects of tributyrin supplementation on ruminal microbial protein yield,fermentation characteristics and nutrients degradability in adult Small Tail ewes

Two trials were conducted to assess the effects of tributyrin (TB) supplementation on ruminal microbial protein yield and fermentation characteristics in adult sheep. In an in vitro trial, substrate was made to offer TB at 0, 2, 4, 6, and 8 g/kg on a dry matter (DM) basis and incubated for 48 hr. In an in vivo trial, 45 adult ewes were randomly assigned by initial body weight (55 ± 5 kg) to five treatments of nine animals over an 18‐day period. Total mixed ration was made to offer TB to ewes at 0, 2, 4, 6, and 8 g/kg on a DM basis. The in vitro trial showed that TB enhanced apparent degradation of DM (p = .009), crude protein (p < .001), neutral detergent fiber (p = .007) and acid detergent fiber (p = .010) and increased methanogenesis (p < .001), respectively. The in vivo trial showed that TB decreased DM intake (p < .001) and enhanced rumen microbial N synthesis (p < .001), respectively. Both in vitro and in vivo trials showed that TB increased total volatile fatty acid concentration and enhanced fibrolytic enzyme activity. The results indicated that TB might exert positive effects on microbial protein yield and fermentation in the rumen.     

Effects of feeding condensed barley distillers soluble on growth rate,ruminal fermentation,plasma metabolites,and myofiber properties of the longissimus thoracis muscle in Japanese Black calves

This study evaluated the effects of condensed barley distillers soluble (CBDS) on growth rate, rumen fermentation, plasma metabolite, and myofiber properties, and gene expression related to metabolism in the skeletal muscles of Japanese Black calves, compared with soybean meal and corn. Twenty‐four calves were divided into four groups: fed 5% CBDS based on the hay dry matter weight (low CBDS) and fed soybean meal and corn at the same nutrition level (control); and fed 15% CBDS based on the hay dry matter weight (high CBDS) and fed soybean meal and corn at the same nutrition level (high soy). The daily gain was larger in the low (p = 0.08) and high (p < 0.05) CBDS groups compared with the control group. In the CBDS‐fed groups, plasma β‐hydroxybutyric acid concentrations were significantly higher at 6 months of age (p < 0.05), the percentage of type I myofibers was significantly lower and their diameters were significantly larger at 9 months of age (p < 0.05), and carnitine palmitoyltransferase 1b mRNA expression was significantly lower (p < 0.05) and citrate synthase mRNA expression tended to be lower (low; p = 0.06, high; p = 0.05) compared with control group. Thus, feeding CBDS promotes growth and leads to animals with more glycolytic and less oxidative muscle metabolism.     

Effects of pistachio by‐products on digestibility,milk production,milk fatty acid profile and blood metabolites in Saanen dairy goats

The objective of this study was to investigate the effects of pistachio by‐products (PBP) on nutrient digestibility, blood metabolites and milk fatty acid (FA) profile in Saanen dairy goats. Nine multiparous lactating Saanen goats (on day 90 post‐partum, 45 ± 2/kg BW) were randomly assigned to a 3 × 3 Latin square design with three treatment diets: 1) control diet (alfalfa hay based), 2) 32% PBP and 3) 32% PBP + polyethylene glycol (PEG‐4000; 1 g/kg dry matter). Each period lasted 21 days, including 14 day for treatment adaptation and 7 day for data collection. Pistachio by‐products significantly decreased (p < 0.01) crude protein (CP) digestibility compared with the control diet (64.4% vs. 58.7%), but PEG addition did not differ for CP digestibility of goats fed 32% PBP + PEG and those fed the two other diets. The digestibility of NDF tended (p = 0.06) to decrease for goats fed PBP compared with those fed the control diet. Yields of milk and 4% fat‐corrected milk were not affected by dietary treatments. Compared with the control diet, PBP supplementation appreciably changed the proportions of almost all the milk FA measured; the main effects were decreases (p < 0.01) in FA from 8:0 to 16:0 and increases (p < 0.01) proportions of cis‐9, trans‐11 18:2 and trans‐11 18:1, monounsaturated FA, polyunsaturated FA and long‐chain FA. The saturated FA, short‐chain FA and medium‐chain FA proportions were lower (p < 0.01) in goats fed the two PBP supplemented diet than in those fed the control diet and PEG addition led to intermediate proportions of saturated FA, unsaturated and monounsaturated FA. Inclusion of PBP in the diet decreased (p < 0.01) plasma concentrations of glucose and urea nitrogen compared with the control diet. It was concluded that PBP can be used as forage in the diet of dairy goats without interfering with milk yield. Inclusion of 32% PBP in the diet of dairy goats had beneficial effects on milk FA profile but PEG addition to PBP did not contribute to enhance further milk FA profile.     

Use of NaHCO3 and MgO as additives for sheep fed only pasture for a restricted period of time per day: effects on intake,digestion and the rumen environment

Effects of NaHCO₃ and MgO buffer addition on intake and digestive utilization of a pasture were studied in wethers allowed a restricted time of access to forage. Twelve wethers housed in metabolic cages and fed fresh forage (predominantly Lotus corniculatus) ad libitum for 6 h/d were randomly assigned to one of the following treatments: a control forage without buffer (C) or a forage plus buffer composed of a mixture of 750 g/kg NaHCO₃ and 250 g/kg MgO at 20 g/kg dry matter intake (B). Feeding behaviour, feed and water intake and digestibility, urine output, Na urine elimination, kinetics of passage, ruminal pH and ammonia concentration, N balance and ruminal microbial N synthesis were determined in vivo, and the ruminal liquor activity was evaluated in vitro by fermentation of wheat straw. Addition of buffer increased total water intake (p = 0.05), Na urinary output (p = 0.01), purine derivative excretion in urine (p = 0.05) and tended to decrease mean total retention time in the digestive tract (p = 0.09). However, buffer addition increased ruminal pH (p < 0.001) and tended to decrease the ammonia concentration (p = 0.05). That use of buffer decreased ruminal activity was evidenced by a lower volume of gas produced in vitro (p = 0.01) possibly due to a lower microbial concentration in rumen liquor. The higher rumen dilution rate, likely due to a higher water intake, seems to have been the key driver of the actions of buffer supplementation on the rumen environment. Moreover, addition of NaHCO₃ led to an increased urinary Na excretion, which should be considered due to its likely negative environmental impacts.     

Subtropical goats ovulate in response to the male effect after a prolonged treatment of artificial long days to stimulate their milk yield

The objectives of this study were to determine (i) if in subtropical goats that gave birth during mid‐December, the exposition to an artificial long‐day photoperiod consisting in only 14 hr of light per day can increase the milk yield and (ii) to test whether these females can respond to the male effect at the end of the prolonged photoperiodic treatment. In experiment 1, 17 lactating goats were maintained under natural short days (control group), while another 22 goats were maintained under artificial long days (treated group) consisting in 14 hr light and 10 hr darkness starting at day 10 of lactation. The continuous exposition to an artificial long‐day photoperiod produced an increase in the milk yield level during the first 110 days of lactation (time × treatment interaction; p = .01), while none of the milk components were modified due to the photoperiodic treatment (p > .05). In experiment 2, all control and treated anovulatory goats were submitted to the male effect using photostimulated males. All females showed oestrous behaviour within the first 10 days that were in contact with males (100% in both groups; p > .05). Thus, the latency to onset of oestrus did not differ between females from control (58.2 ± 3.0 hr) and treated (62 ± 4.6 hr) groups. Male exposition provoked ovulation independently if females were previously under long days or natural photoperiod (96 vs 100%, respectively; p = .79). It was concluded that exposure to 14 hr of light per day in subtropical goats that gave birth in late autumn stimulates milk yield without preventing the ovulation in response to the male effect at the end of the prolonged photoperiodic treatment.     

饲粮中添加酵母培养物对舍饲牦牛瘤胃发酵参数及微生物区系的影响

本试验旨在研究饲粮中添加酵母培养物(YC)对舍饲牦牛瘤胃发酵参数及微生物区系的影响。试验选取4岁、初始体重为(180.31±29.73)kg的健康麦洼公牦牛36头,随机分为4组,每组9个重复,每个重复1头牦牛,分别饲喂YC添加水平为0(Ⅰ组)、0.5%(Ⅱ组)、1.0%(Ⅲ组)和1.5%(Ⅳ组)的全混合日粮。预试期10 d,正试期80 d。结果表明:1)随着饲粮YC添加水平的升高,瘤胃微生物蛋白(MCP)含量显著升高(P<0.05),pH有呈线性降低的趋势(P=0.058),氨态氮(NH3-N)含量有呈二次曲线变化的趋势(P=0.055),乙酸比例及乙酸/丙酸呈显著线性降低(P<0.05),丙酸和丁酸比例呈显著线性增加(P<0.05),总挥发性脂肪酸(TVFA)含量无显著变化(P>0.05)。2)舍饲牦牛瘤胃微生物多样性指数除Chao指数外,其余各指数组间无显著差异(P>0.05)。3)门水平上,4组的优势菌门均为拟杆菌门、厚壁菌门和变形菌门。随着饲粮YC添加水平的升高,疣微菌门的相对丰度呈显著线性升高(P<0.05),Saccharibacteria的相对丰度呈显著线性降低(P<0.05),互养菌门的相对丰度呈显著二次曲线变化(P<0.05),变形菌门和纤维杆菌门的相对丰度有呈二次曲线变化的趋势(P=0.065,P=0.064)。属水平上,普雷沃菌属、拟杆菌目BS11和理研菌科RC9为优势菌属,随着饲粮YC添加水平的升高,克里斯滕森菌科R7的相对丰度呈显著线性降低(P<0.05),与pH和NH3-N含量呈显著正相关(r>0.500,P<0.05),奎因氏菌属的相对丰度呈显著线性降低(P<0.05),与TVFA含量呈显著正相关(r=0.460,P<0.05),瘤胃球菌科UCG-001和瘤胃球菌科UCG-014的相对丰度呈显著线性降低(P<0.05),与pH呈显著正相关(r>0.500,P<0.05),瘤胃球菌科UCG-011和瘤胃球菌属2的相对丰度呈显著二次曲线变化(P<0.05)。综上所述,在舍饲牦牛饲粮中添加YC显著影响了瘤胃中微生物的丰富度,影响门和属水平微生物的组成,进而对瘤胃发酵参数产生影响。     

Effects of Antimicrobial peptides on egg production,egg quality and caecal microbiota of hens during the late laying period

This study was conducted to determine the effects of diet supplementation of laying hens with antimicrobial peptides (AMP) on egg production, egg quality and caecal microbiota. A total of 360 Hy‐Line Brown laying hens (72 weeks old) were divided into three groups with four replicates of 30 birds each. The laying hens were fed with the basal diet (Control), the basal diet + 50 mg/kg AMP (group 1) and the basal diet + 100 mg/kg AMP (group 2). The experiment lasted for 45 d. Eggs were collected daily and caecal samples were collected at the end of the experiment. The results showed that AMP supplementation caused a significantly increased laying rate and decreased feed/egg ratio (p ＜ .05). Meanwhile, a distinctive difference in cecal microbiota was observed between AMP and control groups and the average values of microbial diversity and richness were lower in the AMP group than in the control group. At the phylum level, the relative abundance of Verrucomicrobia and Cyanobacteria were lower in the AMP group than in the control group. In conclusion, the results indicated that dietary supplementation with AMP can improve egg production and affect the cecal microbial community membership and structure of hens during late laying period.     

Effects of rumen‐protected methionine on milk production in early lactation dairy cattle fed with a diet containing 14.5% crude protein

We evaluated the influence on milk production of feeding early lactation cows a diet that included 14.5% crude protein (CP) and that did not meet methionine (Met) requirements or that met them by supplying rumen‐protected Met (RPMet). Thirty‐nine multiparous Holstein cows were allocated into two groups. For 15 weeks after calving, each group was fed one of the two total mixed rations, Control (n = 20) or Treatment (n = 19). The Treatment group received added RPMet at 0.034% (8 g/day) of the Control diet on dry matter basis. The adequacies of Met for the Control and Treatment groups were 96% and 106%, respectively, and for other amino acids, >110%. The CP level (14.5%) was 1 percentage point lower than that recommended by the Japanese Feeding Standard (2006). No between‐group differences were found in milk yield (40 kg/day), milk composition, plasma profile, rumen fermentation, nitrogen balance, or cow health. Met intake and the amount of rumen‐undegradable feed Met were higher in the Treatment group (p < 0.05). Microbial Met and total metabolizable Met did not differ between groups. Supplying RPMet in a 14.5% CP diet during early lactation did not dramatically affect milk production, because the amount of total metabolizable Met was unchanged.     

Influence of dietary condensed tannins from sericea lespedeza on bacterial loads in gastrointestinal tracts of meat goats

This research assessed the potential use of a low input forage containing a high amount of condensed tannins (CT) to reduce foodborne pathogens prior to slaughter of meat goats. In a completely randomized design, twenty Kiko × Spanish intact male kids (BW = 19.2 ± 0.74 kg) were fed ground sericea lespedeza [SL; Lespedeza cuneata (Dum-Cours) G. Don; 2 pens], a high-CT legume, or bermudagrass hay [BG; Cynodon dactyon (L.) Pers.; 2 pens], at 75% of daily intake with a corn-based supplement (25% of intake) for 14 weeks (n = 10 goats/treatment). At the end of the feeding trial, the animals were slaughtered using standard procedures. Immediately after evisceration, rumen and rectal samples were collected to assess bacterial loads and volatile fatty acids in the rumen. Concentrations of rumen volatile fatty acids were significantly different between dietary treatments. Goats fed SL hay had higher (P < 0.05) contents of butyric (8.66 vs 7.16 mM), isobutyric (1.94 vs 1.44 mM), isovaleric (3.03 vs 2.13 mM), and valeric (1.43 vs 1.07 mM) acids than those fed BG hay; however, the content of acetic acid (78.6 vs 64.4 mM) was higher (P < 0.05) in the BG-fed groups than in SL-fed groups. Escherichia coli (2.33 vs 1.13 log₁₀ CFU/g) counts of rumen contents were higher (P < 0.05) in the SL-fed group compared with the BG-fed group. However, E. coli counts in feces were not different (P > 0.05) between dietary treatments. The high-CT influenced (P < 0.05) total plate counts in the feces; and the total plate counts in feces of SL- and BG-fed goats were 4.95 and 6.57 log₁₀ CFU/g, respectively. The results indicated that high CT in the diet might influence rumen volatile fatty acid composition, but might not reduce the bacterial loads in gastrointestinal tracts of meat goats.     

Effects of Saccharomyces cerevisiae supplementation on growth performance,plasma metabolites and hormones,and rumen fermentation in Holstein calves during pre‐ and post‐weaning periods

This study aimed to evaluate the effects of supplementing Saccharomyces cerevisiae (SC) during the pre‐ and post‐weaning periods on growth, metabolic and hormonal responses, and rumen fermentation in calves. Three‐week‐old Holstein calves were assigned to either control (n = 12) or SC group (n = 12), the latter of which received 2 × 10⁹ cfu/day of SC. The experiment was conducted over a period of 7 weeks around weaning. Daily gain (DG) in the SC group was higher (p < .05) than that in the control group. In the SC group, plasma glucose, insulin, and growth hormone (GH) concentrations were higher (p < .05) and concentrations of glucagon and insulin‐like growth factor 1 (IGF‐1) tended to be higher (p < .1) than in the control group. Proportion of rumen propionate and concentration of rumen ammonia nitrogen at 10 weeks of age were greater (p < .05) in the SC group than that in the control group. Supplementation of SC around weaning may improve dietary nutrient and energy availability and increase plasma GH and IGF‐1 concentrations. These changes observed in SC‐supplemented calves could be closely related to the improvement of DG.     

青贮饲用油菜对育肥期山羊瘤胃发酵参数及微生物多样性的影响

本试验旨在研究青贮饲用油菜对山羊瘤胃发酵参数及微生物多样性的影响。将24只3月龄左右宜昌白山羊[平均体重(14.83±0.32) kg,公母各半]随机分为2组。试验组饲喂含有青贮饲用油菜的全混合饲粮,对照组饲喂含有青贮全株玉米的全混合饲粮,预试期7 d,正饲期90 d。试验结束时,每组屠宰6只羊,取瘤胃液测定pH、氨态氮、瘤胃液菌体蛋白质、挥发性脂肪酸等指标,并采用16S高通量测序方法分析瘤胃中菌群结构。结果表明,试验组与对照组山羊的平均日增重、干物质采食量和料重比无显著差异(P>0.05)。试验组与对照组间山羊瘤胃液pH值、氨态氮无显著差异(P>0.05);试验组山羊瘤胃液菌体蛋白含量和异丁酸含量显著高于对照组(P<0.05),其他挥发性脂肪酸含量差异不显著(P>0.05);瘤胃菌群结构分析结果表明,试验组和对照组相对丰度大于0.1%的菌门,分别有15和14个,两组中共有的菌门按照丰度排序依次是拟杆菌门、厚壁菌门、变形菌门、螺旋体门和Saccharibacteria,但各菌门丰度组间差异不显著(P>0.05)。属水平上,两个组山羊瘤胃液中普雷沃氏菌属的微生物含量均最多。试验组与对照组有显著差异的菌群Prevotella_1丰度从21.10%减少到16.66%,模糊分类群丰度从1.95%增加到3.19%(P<0.05)。综上所述,饲喂青贮饲用油菜能保持山羊瘤胃内环境及微生物菌群结构稳定,维持瘤胃正常发酵。     

Contribution of different rumen microbial groups to gas,short‐chain fatty acid and ammonium production from different diets—an approach in an in vitro fermentation system

In this study, the relative contribution of different microbial groups to ruminal metabolism was investigated for different diets. The rumen microbial cultures included whole rumen fluid, fungi + protozoa, bacteria + protozoa, protozoa and bacteria + fungi and were established by physical and chemical methods. Gas production, short‐chain fatty acid (SCFA) and ammonium production were measured at 24 hr in in vitro incubations using the Hohenheim gas test (HGT) procedure. Seven donor animal diets with different concentrate‐to‐roughage ratios (C:R: 10:90, 30:70, 50:50, 70:30, 70:30BC (BC = NaHCO₃), 90:10 and 90:10BC) and five HGT diets (C:R: 10:90, 30:70, 50:50, 70:30 and 90:10) were formulated. Incubations in the HGT were always based on inoculum from sheep diets with the respective C:R ratio. Gas and ammonium production increased (p < 0.001) as a result of a gradual increase in concentrate proportion of the diets. In general, SCFA production followed the same trend. Whole rumen fluid and bacteria + fungi produced approximately 50% higher gas volume than protozoa and fungi + protozoa fractions, whereas gas production with bacteria + protozoa was at an intermediate level. Coculture of protozoa either with bacteria or with fungi produced more ammonium. Populations without bacteria were characterized by a particularly high acetate/propionate ratio. Although an interaction between microbial group and diet was observed for several variables, no clear direction could be established. Manipulating rumen fluid by selectively suppressing specific rumen microbial groups may be a helpful tool in elucidating their role in nutrient degradation and turnover in vitro.