Partially substituting alfalfa hay with hemp forage in the diet of goats improved feed efficiency, ruminal fermentation pattern and microbial profiles.

The use of hemp as a forage source in livestock diets has been less studied because bioactive residues in animal tissues may pose a risk to consumers. This study investigated the effects of partial substitution of alfalfa hay (AH) with hemp forage (HF) in growing goat diets on growth performance, carcass traits, ruminal fermentation characteristics, rumen microbial communities, blood biochemistry, and antioxidant indices. Forty Xiangdong black goats with body weight (BW) 7.82 ± 0.57 kg (mean ± SD) were grouped by BW and randomly assigned into one of the four treatment diets (n = 10/treatment) in a completely randomized design. The goats were fed ad libitum total mixed rations containing 60% forage and 40% concentrate (DM basis). The diets included control (CON; 60% AH and 40% concentrate), 55% AH and 5% HF (HF5), 50% AH and 10% HF (HF10), and 40% AH and 20% HF (HF20). Increasing the substitution of HF for AH linearly decreased (P < 0.01) DM intake and improved feed conversion efficiency. However, final BW, average daily gain, carcass traits, meat quality, and most blood biochemistry indices did not differ among treatments. The ruminal NH3-N concentration and blood urine nitrogen linearly increased (P < 0.01) with increasing substitution rate of HF, whereas the total volatile fatty acids concentration quadratically changed (P < 0.01). Substitution of AH with HF had no effect on the diversity and richness of ruminal microbes, though it linearly decreased (P = 0.040) Prevotella_1 and linearly increased (P = 0.017) Rikenellaceae_RC9_gut_group. The cannabinoids and/or their metabolites were detected in both ruminal filtrates (8) and plasma (4), however, no detectable cannabinoid-related residues were observed in meat. These results indicate that the HF could be used to partially substitute AH in goat diets, whereas the effects vary between substitution rates of HF for AH. Although no cannabinoid-related residues were detected in meat, the presence of cannabinoids residues in blood warrants further study of HF feeding to confirm the cannabinoids residues are not present in the animal products.

Brittle Culm 15 mutation alters carbohydrate composition, degradation and methanogenesis of rice straw during in vitro ruminal fermentation.

Brittle Culm 15 (BC15) gene encodes a membrane-associated chitinase-like protein that participates in cellulose synthesis, and BC15 gene mutation affects cell wall composition in plant, such as cellulose or hemicellulose. The present study was designed to investigate the changes of carbohydrates composition in bc15 mutant straw, and the resulting consequence on rumen fermentation, methanogenesis, and microbial populations (qPCR) during in vitro ruminal fermentation process. Two substrates, bc15 mutant and wild-type (WT) rice straws, were selected for in vitro rumen batch culture. The first experiment was designed to investigate the kinetics of total gas and CH4 production through 48-h in vitro ruminal fermentation, while the second experiment selected incubation time of 12 and 48 h to represent the early and late stage of in vitro ruminal incubation, respectively, and then investigated changes in biodegradation, fermentation end products, and selected representative microbial populations. The bc15 mutant straw had lower contents of cellulose, neutral detergent fiber (NDF) and acid detergent fiber (ADF), and higher contents of water-soluble carbohydrates, neutral detergent solubles (NDS) and monosaccharides. The bc15 mutant straw exhibited a distinct kinetics of 48-h total gas and CH4 production with faster increases in early incubation when compared with WT straw. The bc15 mutant straw had higher DM degradation, NDF degradation and total volatile fatty acid concentration at 12 h of incubation, and lower NDF degradation and CH4 production at 48 h of incubation, together with lower acetate to propionate ratio and ADF degradation and higher butyrate molar percentage and NDS degradation at both incubation times. Furthermore, the bc15 mutant straw resulted in greater 16S gene copies of F. succinogenes, with lower 18S gene copies of fungi at both incubation times. These results indicated that the BC15 gene mutation decreased fibrosis of cell wall of rice straw, enhanced degradation at the early stage of rumen fermentation, and shifts fermentation pattern from acetate to propionate and butyrate production, leading to the decreased volume and fractional rate of CH4 production. However, BC15 gene mutation may enhance hardenability of cell wall structure of rice straw, which is more resistant for microbial colonization with decreased fiber degradation. Thus, this study modified rice straw by manipulating a cell wall biosynthesis gene and provides a potential strategy to alter degradation and CH4 production during in vitro ruminal fermentation process.

Effects of urea supplementation on the nutritional quality and microbial community of alfalfa (Medicago sativa L.) silage.

The objectives of this study were to evaluate the contribution of urea on the nutritional quality and microbial community of ensiled alfalfa (Medicago sativa L.). Alfalfa silage was control group without urea (AL), supplementation with 0.5% urea (AU1), or supplementation with 1% urea (AU2). The silage tanks were opened and sampled after silage at 0, 15, 30, and 60 d. Results showed that AU2 had higher pH, ratio of (ammonia-N)/(total nitrogen) (NH3-N/TN) and crude protein (CP) content than those in AL and AU1, while AU1 had higher acid detergent fiber (ADF) than that in AL and AU2 after 15 d silage. Richness and diversity indices of microbial communities in silage were no significant differences among AL, AU1 and AU2 group. Proteobacteria (58.23%) and Firmicutes (40.95%) were the predominant phylum in three groups during the silage process. The percent of community abundances on genera level of Enterobacteriaceae (37.61%) and Klebsiella (41.78%) in AL were a little higher than those in AU1 (30.39%, 25.02%) and AU2 (33.48%, 26.92%). These results showed that silage with urea alone could not improve the quality of alfalfa.

Dietary ε-Polylysine Affects on Gut Microbiota and Plasma Metabolites Profiling in Mice.

Given the antibacterial effects of ε-polylysine acting on cell membranes, and that glycerol phospholipids are important components of the cell membrane, we hypothesized that ε-polylysine may regulate glycerophospholipid metabolism by modifying the gut microbiota. To test this hypothesis, we treated post-weaning C57 mice with different levels of ε-polylysine (0, 300, 600, and 1,200 ppm) in their basic diet. The growth performance and morphology of intestine were then determined. Modification of the gut microbiota and their function were analyzed using 16S rDNA sequencing. Metabolite identification was performed using the LC-MS method. The results showed that body weight decreased with an increasing supplemental level of ε-polylysine from 5 to 7 weeks (P < 0.05), but no significant difference was observed after 8 weeks (P > 0.05). Supplementation with 1,200 ppm ε-polylysine changed the morphology of the jejunum and ileum, increased the villus length, decreased the crypt depth of the jejunum, and decreased the villus length and crypt depth of the ileum (P < 0.05). ε-Polylysine shifted the intestine microbiota by changing alpha diversity (Chao 1, observed species, Shannon, and Simpson indices) and varied at different times. ε-polylysine decreased Firmicutes and increased Bacteroidetes at 4 week, but increased Firmicutes and decreased Bacteroidetes at 10 week. ε-Polylysine regulated genera associated with lipid metabolism such as Parabacteroides, Odoribacter, Akkermansia, Alistipes, Lachnospiraceae UCG-001, Collinsella, Ruminococcaceae, and Intestinimonas. During the adult period, the genera Alistipes, Lachnospiraceae UCG-001, and Streptomyces were positively associated with PC, PE, LysoPC, LysoPE, 1-Arachidonoylglycerophosphoinositol and OHOHA-PS (R > 0.6, P < 0.001), but changes in Blautia, Christensenellaceae R-7 group, Odoribacter, Allobaculum, Ruminococcaceae UCG-004, Ruminococcaceae UCG-005, and Lachnospiraceae UCG-010 were negatively correlated with glycerophospholipid metabolites (R < -0.6, P < 0.001). The abundance of glycerophospholipid metabolites, including PC, PE, lysoPC, and lysoPE, were decreased by ε-polylysine. Furthermore, ε-polylysine reduced the incidence of the genera including Ruminococcus, Prevotella, Prevotellaceae, Butyricimonas, and Escherichia-Shigella and reduced the abundance of Faecalibaculum, Christensenellaceae R-7 group, Coriobacteriaceae UCG-002. In conclusion, ε-polylysine modified gut microbiota composition and function while also restraining pathogenic bacteria. The glycerophospholipid metabolism pathway and associated metabolites may be regulated by intestinal bacteria.

Multi-omics reveals host metabolism associated with the gut microbiota composition in mice with dietary ε-polylysine.

This study aimed to assess the influence of dietary supplementation of ε-polylysine on the gut microbiota and host nutrient metabolism, which is not systematically discussed by multi-omics analysis. A total of 40 mice were randomly divided into two groups exposed to either a basal diet (AIN-76A) or a basal diet with 150 ppm ε-polylysine. Fecal samples were collected for gut bacteria identification. Liver and plasma samples were collected for metabolomic and proteomic analyses. The results showed that ε-polylysine decreased the body weight of mice and affected the presence of certain types of intestinal microorganisms. The richness of the microbiota and number of phyla increased with age. ε-Polylysine affected the presence of genera and species, and either regulated or took part in the metabolism of energy, nitrogen, amino acids, lipids, carbohydrates, glycans, cofactors, and vitamins. The metabolite profiling showed that lipid and lipid-like molecules metabolites occupied the majority percent of plasma and liver metabolites. Additionally, ε-polylysine regulated the key role of metabolites and related metabolic enzymes in the metabolic pathways, especially phospholipid metabolism. In conclusion, dietary ε-polylysine improved the immunity of growing mice, and had a greater effect on the anabolism of nutrients in adult mice.

Alfalfa Silage Treated With Sucrose Has an Improved Feed Quality and More Beneficial Bacterial Communities.

Alfalfa silage is one of the main roughages in the production of dairy cow, which can provide nutrition with high quality to improve milk quality and production. Sucrose additions have been widely used to improve the silage quality. In this study, the effects of sucrose on the fermentation quality and bacterial communities of alfalfa silage were investigated here using 0, 0.5, and 1% sucrose ensiling treatments for 15, 30, and 60 days. The ensiling time significantly decreased the crude fiber content and increased the ammonia nitrogen, acetic acid content, and the relative abundance of Enterococcus in the silages. The 1% sucrose-treated silage at 60 days had the lowest neutral detergent fiber acid, acid detergent fiber, and crude fiber content and the highest relative feed value. Moreover, sucrose-treated silage contained less acetic acid, propionic acid, and butyric acid, and had a lower pH than the controls for each duration. Enterobacteriaceae, Klebsiella, and Enterococcus were the dominant genera in all groups, and the relative abundance of Enterococcus and Lactobacillus was higher in the 1% sucrose-treated group than in the control. These results suggested that sucrose supplementation could improve alfalfa silage quality and increase its beneficial bacterial content.

Substitution of ramie (Boehmeria nivea) for alfalfa in improving the carcass and meat quality of Liuyang Black goats.

Ramie (Boehmeria nivea) is noted for the production of a large biomass that has a high protein content and is rich in antioxidants. It may thus serve as a high-quality forage material to replace alfalfa and improve the meat quality of farmed animals. In this study, we evaluated the carcass characteristics and meat quality of goats when 0, 35%, 75%, and 100% of dietary alfalfa was replaced with ramie. Crude protein content (linear, P < 0.0001) and key muscle color values at 24 h after slaughter decreased with increasing ramie levels. The content of most individual amino acids, non-essential amino acids (NEAA), total amino acids (TAA), branched chain amino acids (BCAA), functional amino acids (FAA), and flavor amino acids (DAA) decreased (P < 0.05) with increasing dietary ramie. The diet in which 35% of alfalfa was replaced with ramie yielded meat with the highest amino acid content, whereas the fatty acid profile was unaffected by the inclusion of ramie. These results indicate that ramie could be used as a potential dietary forage resource for goats, and that substituting 35% of alfalfa with ramie, which is equivalent to 126 g/kg DM content, would be optimal in terms of goat meat quality.

Fermented Soybean Meal Replacement in the Diet of Lactating Holstein Dairy Cows: Modulated Rumen Fermentation and Ruminal Microflora.

This study was conducted to examine the influences of replacing soybean meal (SBM) with fermented soybean meal (FSBM) in the diet of lactating Holstein cattle on rumen fermentation and ruminal bacterial microbiome. Twenty-four lactating Chinese Holstein dairy cattle were assigned to each of the two treatments in a completely randomized design: the SBM group [the basal total mixed ration (TMR) diet containing 5.77% SBM] and the FSBM group (the experimental TMR diet containing 5.55% FSBM). This trial lasted for 54 days (14 days for adjustment and 40 days for data and sample collection), and samples of rumen liquid were collected on 34 d and 54 d, respectively. The results showed that replacing SBM with FSBM significantly increased the molar percentages of propionate (P < 0.01) and valerate (P < 0.05), but reduced the total volatile fatty acid (TVFA) concentration (P < 0.05), butyrate molar proportion (P < 0.05), and the acetate to propionate ratio (P < 0.01). The copy numbers of total bacteria (P < 0.05), Fibrobacter succinogenes (P < 0.01), Selenomonas ruminantium (P < 0.01), and Prevotella spp. (P < 0.05) in the FSBM group were greater, while the density of Prevotella ruminicola (P < 0.05) was lower than those in the SBM treatment. Additionally, Succiniclasticum ruminis and Saccharofermentans acetigenes were significantly enriched (P < 0.05) in the rumen fluid of FSBM-fed cows, despite the fact that there was no remarkable difference in the Alpha diversity indexes, structure and KEGG pathway abundances of the bacterial community across the two treatments. It could hence be concluded that the substitution of FSBM for SBM modulated rumen fermentation and rumen bacterial microbiota in lactating Holstein dairy cows. Further research is required to elucidate the relevant mechanisms of FSBM, and provide more insights into the application of FSBM in dairy cattle.

Dietary Supplementation of ε-Polylysine Beneficially Affects Ileal Microbiota Structure and Function in Ningxiang Pigs.

Intestinal microbiota plays an important role in the health of animals. However, little is known about the gut microbiota in Ningxiang pigs. Thus, we investigated how dietary supplementation with different ε-polylysine concentrations (0, 20, 40, 80, and 160 ppm) affected the ileal microbiota in Ningxiang pigs using a replicated 5 × 5 Latin square method. Each experimental period included 10 days for diet adaptation, 3 days for feces collection and 2 days for digesta collection. The ileal contents were collected and used for sequencing of the V3-V4 hypervariable region of the 16S rRNA gene. The results revealed that ε-polylysine significantly decreased the digestibility of crude protein and crude fiber, as well as the utilization of metabolizable energy (P < 0.05). The relative abundances of 19 bacterial genera significantly increased, while those of 26 genera significantly decreased (P < 0.05). In addition, ε-polylysine increased the abundance of some bacteria (e.g., Faecalibacterium, Bifidobacterium, and lactic acid bacteria) and inhibited some other bacteria (e.g., Micrococcaceae, Acinetobacter, Anaerococcus, Peptoniphilus, Dehalobacterium, Finegoldia, Treponema, and Brevundimonas). Furthermore, based on the 16S rRNA gene data and data from the precalculated GreenGenes database, bacterial communities in the ileal contents exhibited enhanced functional maturation, including changes in the metabolism of carbohydrates, amino acids (e.g., alanine, lysine, tryptophan, cysteine, and methionine), cofactors, and vitamins (e.g., biotin, thiamine, and folate), as well as in the activity of the insulin signaling pathway. This study suggests that ε-polylysine may influence the utilization of feed nutrients by Ningxiang pigs, including proteins, lipids, metabolizable energy, and fiber, by regulating the gut microbiota.

High-potency white-rot fungal strains and duration of fermentation to optimize corn straw as ruminant feed.

Five white-rot fungi Pleurotus ostreatus, Lentinus edodes, Hericium erinaceus, Pleurotus eryngii and Flammulina filiformis were studied (solid-state incubation and in vitro gas production) to determine lignin degradation and optimal duration of fermentation of corn straw. All fungi significantly decreased lignin, with optimal reductions after 28 d. Although cellulose also decreased, L. edodes and P. eryngii minimized these losses. In intro dry matter digestibility, total volatile fatty acid concentration and total gas production of fermented corn straw decreased (P < 0.001) as fermentation was prolonged, with improved rumen fermentability for all fungal treatments except F. filiformis. Total gas production in L. edodes did not decrease but peaked on day 28, whereas F. filiformis reduced methane emission. In conclusion, fermentation of corn straw with P. eryngii or L. edodes for 28 d degraded lignin and improved nutritional value as ruminant feed.

Effects of oral monosodium glutamate administration on serum metabolomics of suckling piglets.

This study was conducted to determine the effects of oral administration with glutamate on metabolism of suckling piglets based on 1 H-Nuclear magnetic resonance (1 H NMR) spectroscopy through the level of metabolism. Forty-eight healthy [(Yorkshire × Landrace) × Duroc] piglets born on the same day with a similar birth bodyweight (1.55 ± 0.20 kg) were obtained from six sows (8 piglets per sow). The piglets from each sow were randomly assigned into four treatments (2 piglets per treatment). The piglets were given 0.09 g/kg body weight (BW) of sodium chloride (CN group), 0.03 g/kg BW monosodium glutamate (LMG group), 0.25 g/kg BW monosodium glutamate (MMG group) and 0.50 g/kg BW monosodium glutamate (HMG group) twice a day respectively. An 1 H NMR-based metabolomics' study found that the addition of monosodium glutamate (MSG) significantly reduced serum citrate content in 7-day-old piglets, while HMG significantly increased serum trimethylamine content and significantly reduced unsaturated fat content in 7-day-old piglets (p < .05). The content of glutamine, trimethylamine, albumin, choline and urea nitrogen was significantly increased and the creatinine content decreased significantly in the 21-day-old HMG (p < .05). Analysis of serum hormones revealed that glucagon-like peptide-1 (GLP-1) content in the 21-day-old HMG was highest (p < .05). The cholecystokinin (CCK) content in the HMG of 7-day-old piglets was lower than that in the LMG (p < .05), and the CCK content in the serum of the 21-day-old MMG was highest (p < .05). The serum leptin levels in the 21-day-old HMG were the lowest (p < .05). The serum insulin content in the 7-day-old MMG was highest (p < .05). This study suggests that MSG plays an important role in the metabolism of sugar, fat and protein (amino acids). These results provide a theoretical basis for designing piglet feed formulations.

Effects of Dietary Alkyl Polyglycoside Supplementation on Lactation Performance, Blood Parameters and Nutrient Digestibility in Dairy Cows.

This study evaluated the effects of alkyl polyglycoside (APG), which is a non-ionic surfactant, on lactation performance, nutrient digestibility and blood metabolites in dairy cows. Twenty dairy cows were randomly divided into four groups and fed a basal diet that included pelleted concentrate, distillers grains, and fresh limpograss. The four treatments included 0, 5.5, 11 and 22 mL APG per kg of pelleted concentrate on a dry matter basis; treatments were defined as APG0, APG5.5, APG11, and APG22, respectively. Dry matter intake was not affected by APG supplementation. There was an increase in milk yield (from 13.96 to 16.71 kg/day) and increases in milk fat (quadratic, p = 0.04), protein (quadratic, p = 0.10), and lactose concentrations (linear, p = 0.07) with increasing APG supplementation. In addition, APG supplementation increased (p ≤ 0.03) the milk fat, protein, solid non-fat, and total solid yields, while the lactose yield increased (linear, p = 0.01) as the APG level increased. Dietary APG supplementation had no effect on nutrient digestibility and blood metabolites. It was concluded that the addition of APG at doses up to 22 mL/kg of pelleted concentrate had positive effects on the milk composition in dairy cows.

Effects of the Forage Type and Chop Length of Ramie Silage on the Composition of Ruminal Microbiota in Black Goats.

The aim of this study was to investigate the effects of the forage type and chop length of ramie (Boehmeria nivea (L.) Gaud.) silage on rumen fermentation and ruminal microbiota in black goats. Sixteen Liuyang black goats (22.35 ± 2.16 kg) were fed with the roughage of corn silage or ramie silage at chop lengths of 1, 2, or 3 cm. The Chao 1 index and the observed number of microbial species differed significantly between the corn and ramie silage groups (p < 0.05); however, Firmicutes (relative proportion: 34.99-56.68%), Bacteroidetes (27.41-47.73%), and Proteobacteria (1.44-3.92%) were the predominant phyla in both groups. The relative abundance of Verrucomicrobia (0.32-0.82%) was lowest for the 2 and 3 cm chop lengths (p < 0.05) and was negatively correlated with rumen pH and propionic acid concentration (p < 0.05), but positively correlated with the ratio of acetic acid to propionic acid (p < 0.05). The ramie silage fermentation quality was highest for the 1 cm chop length, suggesting that moderate chopping produces optimal quality silage.

Substitution of fresh forage ramie for alfalfa hay in diets affects production performance, milk composition, and serum parameters of dairy cows.

We hypothesized that ramie, Boehmeria nivea (a nettle native to Asia), can be used as a high-quality forage to replace alfalfa hay in diets of dairy cows. Accordingly, we aimed to examine the effects of substituting fresh forage ramie for alfalfa (Medicago sativa) hay on production performance, milk composition, and serum parameters of dairy cows. Thirty-two Holstein cows (body weight (BW) = 590 ± 50.6 kg) were randomly divided into four groups of eight cows. The experimental period lasted 10 weeks. The dietary treatments consisted of four proportions of fresh forage ramie (0, 33, 67, and 100%) as a substitute for alfalfa hay (designated as CON, FR33, FR67, and FR100, respectively). On days 69 and 70 of the experimental period, milk and blood samples were collected for analysis. We found no significant differences in the milk yield and milk quality (milk protein percentage, milk fat percentage, and milk lactose percentage) between the treatments. We did find that forage ramie significantly reduced dry matter intake (DMI) and 4% fat-corrected milk (FCM) yield. Meanwhile, no significant differences were detected in serum parameters between the treatments, with the exception of triglyceride (TG) and alanine aminotransferase (ALT). In conclusion, our data indicate that alfalfa hay can be replaced with forage ramie in the diet of Holstein cows in the milk lactation stage, with no negative effects on milk quality and blood parameters.

Effects of enzyme supplementation on the nutrient, amino acid, and energy utilization efficiency of citrus pulp and hawthorn pulp in Linwu ducks.

The objective of this study was to evaluate the effects of enzyme supplementation on the nutrient, amino acid, and energy utilization efficiency of citrus pulp and hawthorn pulp as unusual feedstuffs in Linwu ducks. Forty ducks were assigned to each treatment group and fed diets with or without complex enzyme supplementation. All birds received the same quantity of raw material (60 g) via the force-feeding procedure. With the exception of leucine and phenylalanine, amino acid concentrations in hawthorn pulp were twice those in citrus pulp. Enzyme supplementation significantly increased apparent dry matter digestibility (ADM) of citrus pulp (P < 0.05), but had no significant effects (P > 0.05) on the apparent and true utilization rates of other nutrients, apparent metabolizable energy (AME), or true metabolizable energy (TME), from citrus pulp and hawthorn pulp by Linwu ducks. However, enzyme supplementation significantly increased (P < 0.05) apparent gross energy, true gross energy, AME, and TME of hawthorn pulp for Linwu ducks. There were no differences in the apparent and true utilization rates of amino acids from citrus pulp (P > 0.56) between the groups, with the exception of arginine (P < 0.05). There was an increasing trend in the apparent and true utilization rates of alanine (P = 0.06) and tyrosine (P = 0.074) from citrus pulp with enzyme supplementation. The apparent and true utilization rates of threonine in hawthorn pulp were increased significantly (P < 0.05) following enzyme supplementation. The addition of exogenous enzymes improved the forage quality of citrus pulp and hawthorn pulp, which represent potential feed resources for husbandry production.

Influence of Oleic Acid on Rumen Fermentation and Fatty Acid Formation In Vitro.

A series of batch cultures were conducted to investigate the effects of oleic acid (OA) on in vitro ruminal dry matter degradability (IVDMD), gas production, methane (CH4) and hydrogen (H2) production, and proportion of fatty acids. Rumen fluid was collected from fistulated goats, diluted with incubation buffer, and then incubated with 500 mg Leymus chinensis meal supplemented with different amounts of OA (0, 20, 40, and 60 mg for the CON, OA20, OA40 and OA60 groups, respectively). Incubation was carried out anaerobically at 39°C for 48 h, and the samples were taken at 12, 24 and 48 h and subjected to laboratory analysis. Supplementation of OA decreased IVDMD, the cumulative gas production, theoretical maximum of gas production and CH4 production, but increased H2 production. However, no effect was observed on any parameters of rumen fermentation (pH, ammonia, production of acetate, propionate and butyrate and total volatile fatty acid production). The concentrations of some beneficial fatty acids, such as cis monounsaturated fatty acids and conjugated linoleic acid (CLA) were higher (P < 0.05) from OA groups than those from the control group at 12 h incubation. In summary, these results suggest that the OA supplementation in diet can reduce methane production and increase the amount of some beneficial fatty acids in vitro.

In vitro evaluation on neutral detergent fiber and cellulose digestion by post-ruminal microorganisms in goats.

BACKGROUND: Post-ruminal digestion of fiber has received much less attention than its ruminal digestion. Using in vitro incubation techniques, the present study explored whether variations in fiber digestion occurred in different segments of the post-ruminal tract and whether fiber structure could influence its digestibility. A split plot design was conducted with gut segments (jejunum, ileum, cecum and colon) as main plot and substrates (neutral detergent fiber (NDF) and cellulose (CEL)) as subplot. RESULTS: With the same substrate, the final asymptotic gas volume (V(F)), gas production at t(i) (V(t(i)), digestibility, microbial crude protein (MCP), total bacteria number (TBN), total short-chain fatty acids (TSCFA) and xylanase in incocula from the cecum and colon exceeded (P < 0.01) those in incocula from the jejunum and ileum, while the NH3-N in the former was less (P < 0.01). For the same gut segment, the digestion of CEL was superior to NDF, as reflected in greater V(F), V(t(i)), maximum rate of gas production, digestibility, enzyme activities and SCFA but lower pH and NH3-N. CONCLUSION: The current results imply that the intestinal contents from the cecum and colon have greater potential to digest fiber than those from the jejunum and ileum, and CEL is more easily digested in the post-ruminal tract than NDF.

Unchanged interleukin 6 level of protein and energy restricted goats during late gestation: the role of elevated blood nitric oxide.

Twelve pregnant goats were assigned to three dietary treatments during late gestation, namely control (C: metabolizable energy, 5.75 MJ/kg; crude protein, 12.6% and dry matter basis), 40% protein restricted (PR) and 40% energy restricted (ER), to examine the effects of nutrient restriction on the immune status of pregnant goats. Plasma was sampled on day 90, 125 and 145 from pregnant goats to determine cytokine production (interleukin 2 (IL2), IL6) and tumor necrosis factor α (TNFα)). Peripheral blood mononuclear cells were obtained on day 145 and activated by lipopolysaccharide to determine cytokine production, and then exposed (PR and ER) to sodium nitroprusside (SNP), a nitric oxide (NO) donor, or control to NG-nitro-l-arginine methyl ester hydrochloride (l-NAME), an NO synthase inhibitor to explore the role of NO in regulating cytokine production. Plasma IL2, IL6 and TNFα were not altered during gestation, but NO was increased (P<0.05) at gestation day 145 for PR and ER. In vitro, compared with control, NO was lower for PR and ER (P<0.001), but IL6 was higher for PR (P<0.001) and ER (P=0.11). The addition of SNP decreased IL6 (P<0.001, PR; P=0.12, ER) in the malnourished group, and l-NAME increased (P<0.001) IL6 in control compared to those treatments without SNP or l-NAME. The results indicate that plasma NO acted as a regulator of cytokine function exhibiting negative feedback to maintain steady plasma IL6 concentration in PR or ER goats during late gestation.