Search

Abstract: The objective of this study was to evaluate the effects of 2-methylbutyrate (2MB) supplementation on rumen fermentation, ruminal enzyme activities, urinary excretion of purine derivatives and feed digestibility in the total tract of steers. Eight ruminally cannulated Simmental steers were used in a replicated 4×4 Latin square experiment. The treatments were: control (without 2MB), L2MB, M2MB and H2MB with 8.4, 16.8 and 25.2g 2MB per steer per day, respectively. 2-methylbutyrate was hand-mixed into the concentrate portion. Diet consisted of 60% corn stover and 40% concentrate (dry matter [DM] basis). Dry matter intake (averaged 9kg/d) was restricted to a maximum of 90% of ad libitum intake. Ruminal pH was linearly decreased, whereas total VFA concentration (range of 64.19–71.06mM) was linearly (p <0.01) and quadratically (p <0.01) increased with increasing 2MB supplementation. Ratio of acetate to propionate increased linearly (p <0.01) from 2.53 to 3.80 as 2MB supplementation increased due to the increased in acetate production and decreased in propionate production. Activities of CMCase and xylanase were linearly increased, whereas that of protease was linearly reduced with increasing 2-methylbutyric supplementation. In situ ruminal NDF degradation of corn stover was improved but the CP degradability of soybean meal was decreased with increasing 2MB supplementation. Urinary excretion of purine derivatives was quadratically (p <0.01) changed with altering 2MB supplementation (52.74, 58.50, 59.17 and 54.36mmol/d for control, low, medium and high 2MB supplementation, respectively). Similarly, digestibilities of DM, NDF and CP in the total tract were also linearly and quadratically increased with increasing 2MB supplementation. The present results indicate that supplementation of diet with 2MB improved rumen fermentation and feed digestion in beef cattle. It was suggested that the 2MB stimulated the digestive microorganisms or enzymes in a dose-dependent manner. In the experimental conditions of this trial, the optimum 2MB dose was about 16.8g 2MB per steer per day. [Copyright &y& Elsevier]

This study evaluated the effects of branched-chain volatile fatty acids (BCVFA) supplementation on growth performance, ruminal fermentation, nutrient digestibility, hepatic lipid content and gene expression of dairy calves. Forty-eight Chinese Holstein male calves (10 months of age; 345 ± 6.4 kg of body weight [BW]) were assigned randomly to four treatments with 0, 60, 120 and 180 mg BCVFA per kg BW per day for each calf. Supplemental BCVFA was hand-mixed into the top third of the daily ration and fed to calves for 100 days to the experimental treatments. Supplementation of BCVFA in calves ration increased ADG and feed conversion linearly. Dry matter (DM) intake was unaffected, but digestibilitiy of DM, organic matter, crude protein, ether extract, neutral detergent fibre and acid detergent fibre increased linearly with increasing levels of BCFVA supplementation. Similarly, Supplementation of BCVFA linearly decreased ruminal pH and ammonia-N but increased total VFAs. Molar proportion of acetate linearly increased, whereas propionate linearly decreased and the ratio of acetate to propionate increased linearly with increasing BCVFA in rations. Relative mRNA expressions of peroxisome-proliferator-activated receptor α and carnitine palmitoyl transferase-1 linearly increased with BCVFA levels. The results suggested that BCVFA supplementation improved ruminal fermentation, nutrient digestibility and growth of calves with promoted hepatic lipid oxidation. Due to the unsignificant difference between 120 and 180 mg groups for all parameters, the optimum supplementary dose of BCVFA was 120 mg per kg BW per day. [ABSTRACT FROM AUTHOR]

The study evaluated the effects of rumen protected riboflavin (RPRF) and rumen protected pantothenate (RPPA) on growth performance, nutrient digestibility, rumen fermentation and blood metabolites in bulls. Forty Angus bulls were blocked by body weight and randomly assigned to four treatments in a 2 × 2 factorial design, with factors being 0 or 60 mg riboflavin/kg DM from RPRF and 0 or 35 mg pantothenate/kg DM from RPPA. The experimental period was 80 days, with 20 days for adaptation and 60 days for sample collection. Average daily gain increased and feed conversion ratio decreased, and the changes were greater for supplementing RPPA in diets with RPRF than in diets without RPRF. The populations of total protozoa and Ruminococcus albus increased, but the increases were smaller for supplementing RPPA in diets with RPRF than in diets without RPRF. The total-tract digestibility of dry matter, organic matter, crude protein and neutral detergent fibre increased with RPRF or RPPA addition. The digestibility of acid detergent fibre increased with RPPA addition, and digestibility of non-fibre carbohydrate increased with RPRF addition. The rumen pH and ammonia-N concentration decreased, but total volatile fatty acids concentration and acetate to propionate ratio increased with RPRF or RPPA supplementation. The activities of xylanase and pectinase and populations of total bacteria, R. flavefaciens and Prevotella ruminicola increased with RPRF or RPPA supplementation. The populations of total fungi and Fibrobacter succinogenes increased with RPRF addition, and the activities of α-amylase and protease increased with RPPA addition. The data suggested that RPRF or/and RPPA supply improved growth performance of bulls, and the effect seemed to be due mostly to the vitamins released in the rumen. • Rumen protected riboflavin (RPRF) or rumen protected pantothenate (RPPA) increased growth performance in bulls. • Addition of RPRF or RPPA increased rumen microbial populations in bulls. • Addition of RPRF or RPPA changed rumen fermentation pattern to produce more acetate. • The increase was greater for daily gain with combined RPPA and RPRF than with RPPA or RPRF alone. [ABSTRACT FROM AUTHOR]

Abstract: The objective was to evaluate effects of feeding sorghum-sudan- or alfalfa-based diets on intake, first compartment stomach characteristics, digestibility, nitrogen balance and energy metabolism in alpacas at low altitude (793 m). Six mature alpacas (42±2.3 kg of body weight) were used in a replicated 3×3 Latin square experiment. The treatments were: sorghum-sudan diets (SSD), alfalfa hay diets (AHD) and fresh alfalfa diets (FAD), respectively. Alpacas were housed in metabolism crates and diets were fed for 21 days with 11 d of adaptation and 10 d of sampling. Alpaca was supplemented concentrate with 160 g per alpaca per day and forages were fed at 12 h intervals with water provided ad libitum. First compartment stomach pH and ammonia N were unaffected by forage source, whereas total VFA concentration was different between diets, with the least for FAD (46.8 mM), followed by AHD (51.8 mM) and the highest for SSD (56.1 mM). Ratio of acetate to propionate was greater for AHD and SSD than for FAD diets. The molar proportion of acetate decreased, whereas the molar proportion of propionate increased for FAD relative to AHD and SSD. Redox potential was lower for SSD than for FAD. Surface tension was greater for FAD than for SSD and AHD. Osmolality was lower for FAD than for SSD and AHD. First compartment pressure and methane production tended to be higher for FAD than for SSD (P <0.06) and AHD (P <0.07). Digestibilities of DM, OM and EE were not different between diets. However, the digestibility of CP was lower for AHD relative to SSD and FAD. Digestibilities of NDF and ADF were greater for SSD than for AHD and FAD. Intakes of gross energy (GE) and N were greater for AHD than for FAD and SSD. Digestible energy (DE) was the highest in AHD followed by SSD and FAD. Metablizable energy (ME) was different with the lowest for FAD (3.9 MJ/day), followed by SSD (5.4 MJ/day) and the highest for AHD (8.1 MJ/day). Energy retained was followed the same trend as ME. The results demonstrate variable responses of alpacas to feeding sorghum-sudan or alfalfa diets in terms of dry matter intake, first compartment stomach characteristics, digestibility, nitrogen balance and energy metabolism at low altitude. [Copyright &y& Elsevier]

Abstract: The objective was to investigate the forestomach fermentation characteristics and diet digestibility in alpacas (Lama pacos) and sheep (Ovis aries) fed sorghum-sudan or alfalfa at low altitude (793m). Four 2-year-old alpacas (48±2.3kg) and four 2-year-old sheep (50±1.7kg) were used in a study designed as split-plot in two replicated 2×2 Latin square, respectively, for alpacas and sheep. The main plot was species (alpacas and sheep) and the subplot was forage source (sorghum-sudan and alfalfa). Diet consisted of 700gkg−1 forage, which was either sorghum-sudan or alfalfa, and 300gkg−1 corn-based concentrate (dry matter [DM] basis). The animals were housed in metabolism crates and were fed twice daily for 21 days of each experimental period, with 11 days of adaptation and 10 days of sampling. There was interaction between species and forage on total volatile fatty acid (VFA) concentrations. The concentrations of total VFA decreased by substitution of sorghum-sudan with alfalfa in both species, but the magnitude of the reduction was smaller in alpacas (−17%) than in sheep (−34%). The molar proportions of acetate and BCFA were higher, whereas those of butyrate were lower in alpacas than in sheep with similar proportion of propionate as well as ratio of acetate to propionate between alpacas and sheep. Replacing sorghum-sudan with alfalfa in the diet reduced the ratio of acetate to propionate due to the reduced proportion of acetate and increased proportion of propionate. Ammonia N concentration was about 28% lower in alpacas than in sheep, with no difference between the forages. Redox potential, forestomach pressure, osmolality and methane production were overall lower in alpacas than in sheep. There were no interactions of species with forage source on digestibilities in the total tract. The species had minimal effect on the total digestibilities of nutrients but digestibilities of fibre were lower with alfalfa than with sorghum-sudan diet. The results revealed not only the great differences in forestomach fermentation, but also the similarity of digestibility of nutrients in the total tract between alpacas and sheep at low altitude (793m). [Copyright &y& Elsevier]

• Guanidinoacetic acid (GAA) or betaine (BT) increased growth performance and rumen microbial populations in bulls. • Supplementing BT changed rumen fermentation pattern with greater acetate production. • Supplementing GAA at 0.6 g/kg DM did not affect blood concentrations of folate, homocysteine and methionine. • No additional effect on performance was found with both GAA and BT compared to GAA or BT alone. This study evaluated the influences of guanidinoacetic acid (GAA) and betaine (BT) on growth performance, nutrient digestion and ruminal fermentation in bulls. Forty-four Angus bulls were blocked by live body weight and then randomly divided into four groups in a 2 × 2 factorial design. Betaine of 0 or 0.6 g/kg dry matter (DM) was added to diets containing 0 or 0.6 g/kg DM GAA, respectively. The experiment included a 20 day period for adaptation and a 60 day period for data collection. Average daily gain and feed efficiency were increased by GAA or BT but no further increase was observed for supplementing BT and GAA together than for addition with BT or GAA alone. Supplementary GAA or BT did not influence DM intake but increased apparent digestibility of DM, organic matter (OM), crude protein (CP) and acid detergent fibre (ADF). Digestibility of neutral detergent fibre (NDF) was increased by GAA inclusion but was unaltered with BT provision. Ruminal pH reduced but total volatile fatty acids and ammonia nitrogen elevated with dietary inclusion of GAA or BT. Rumen short chain fatty acids percentages and fermentation pattern were not influenced by GAA. Dietary inclusion of BT increased molar proportions of acetate, valerate, isobutyrate and isovalerate as well as the ratio of acetate to propionate. Rumen populations of Ruminococcus flavefaciens and Fibrobacter succinogenes increased with addition of GAA or BT and the increase was greater when BT was added in diets with GAA compared to diets without GAA. Addition of GAA or BT increased activities of cellobiase, xylanase, α-amylase and protease and populations of total bacteria, cellulolytic bacteria and Ruminobacter amylophilus but did not affect Prevotella ruminicola. Addition of BT increased carboxymethyl-cellulase and pectinase activities and total fungi population. Blood creatine content was increased by GAA or BT and was greater for addition of GAA and BT together than for GAA or BT addition alone. Serum contents of glucose, folate, arginine and methionine were unchanged but total protein increased with GAA or BT provision. Blood homocysteine content was unaffected by GAA but decreased with BT supplementation. The data showed that GAA or BT addition improved growth performance and feed efficiency but supplementing GAA and BT together did not further increase the performance of bulls when compared with GAA or BT inclusion alone. [ABSTRACT FROM AUTHOR]

• Dietary addition of laccase did not affect dry matter intake but elevated average daily gain in Holstein bulls. • Apparent nutrient digestibility and neutral detergent fibre degradability of corn silage increased with laccase addition. • Dietary laccase addition increased total volatile fatty acids and altered fermentation mode to more propionate production. • Addition of laccase increased fiber degrading enzyme activity and copies of total bacteria, fungi and fibrolytic bacteria. This study investigated the impacts of dietary laccase addition on performance, nutrient digestion, rumen fermentation and microbiota in bulls. Eight Holstein bulls with rumen cannula were allocated in a repeated 4 × 4 Latin square experiment design into four groups: control, low-laccase (LL), medium-laccase (ML) and high-laccase (HL) with 0, 0.2, 0.4 and 0.6 g/kg dietary dry matter (DM) of laccase addition, respectively. Addition of laccase did not influence DM intake but higher average daily gain and lower feed conversion ratio were found for bulls in ML group. Apparent nutrients digestibility elevated linearly with increasing laccase supplementation. Digestibility of DM and organic matter in ML, crude protein (CP) in ML and HL as well as neutral detergent fibre (NDF) and acid detergent fibre in LL, ML and HL were higher. Increasing laccase addition quadratically decreased ruminal pH, quadratically increased total volatile fatty acids content and changed ruminal fermentation mode to more propionate formation. Ruminal ammonia-N concentration decreased linearly. Ruminal degradability of concentrate CP and corn silage DM were higher for bulls in ML, but degradability of corn silage NDF was higher for bulls in ML and HL groups. Activities of cellobiase, α-amylase and laccase were higher for bulls in ML group. Populations of total bacteria, methanogens, Fibrobacter succinogenes , Ruminococcus albus , Butyrivibrio fibrisolvens , Prevotella ruminicola and Ruminobacter amylophilus increased linearly, but fungi and R. flavefaciens increased quadratically. Urine excretion of total purine derivatives was higher for bulls receiving medium or high level of laccase supplementation. The results suggested that dietary laccase supplementation increased performance and nutrient digestibility, and the appropriate addition level of laccase was 0.4 g/kg DM in bulls. [ABSTRACT FROM AUTHOR]

• Addition of palm fat powder (PFP) and coated folic acid (CFA) increased milk yield and feed efficiency. • Improved energy balance was only observed for PFP addition. • Addition of CFA stimulated nutrient digestibility, ruminal microbial growth, and fermentation. This study investigated the effects of palm fat powder (PFP) and coated folic acid (CFA) supplementation on performance, energy balance, nutrient digestion, ruminal fermentation and blood metabolites in early lactation dairy cows. Thirty-two multiparous Holstein dairy cows were arranged into four treatments in a 2 × 2 factorial randomized block design. Supplemental PFP (0 g/d [PFP−] or 500 g/d [PFP+]) and CFA (0 mg/d [CFA−] or 135 mg/d of folic acid from CFA [CFA+]) were mixed into the top one-third of the daily ration from d 52 prepartum (based on expected calving date) to d 42 postpartum. Dry matter intake was unaltered but milk yield, milk fat content and feed efficiency increased with PFP or CFA supplementation. Milk protein content was not affected by PFP but increased with CFA supplementation. Body weight change was not affected by PFP or CFA supplementation. Energy balance increased with PFP supplementation but decreased with CFA supplementation. Apparent total-tract digestibility of dry matter, organic matter, crude protein, non-fiber carbohydrates, aNDF, ADF and gross energy, ruminal pH and total volatile fatty acids concentration were unchanged with PFP supplementation but increased with CFA supplementation. Ruminal acetate to propionate ratio was decreased by PFP but increased with CFA supplementation. Lower ammonia-N was observed for PFP or CFA supplementation. Activity of α-amylase and population of Butyrivibrio (B.) fibrisolvens and Ruminobacter (Rb.) amylophilu increased but total protozoa decreased with PFP supplementation. Supplementation of CFA increased activity of cellobiase, xylanase, pectinase, α-amylase and protease and population of total bacteria, fungi, protozoa, Ruminococcus (R.) albus , R. flavefaciens , Fibrobacter succinogenes , B. fibrisolvens , Prevotella ruminicola and Rb. amylophilus. Significant PFP × CFA interaction was not observed during the trial. The results indicated that dietary supplementation of PFP or/and CFA had the potential to improve performance of early lactation dairy cows. [ABSTRACT FROM AUTHOR]

• Dietary rumen-protected folic acid (RPFA) and betaine (BT) addition increased yields of milk and milk fat. • Total tract digestibility of crude protein and fiber components increased with RPFA or BT addition. • Dietary RPFA or BT addition increased ruminal total volatile fatty acids concentration and acetate production. • Addition of RPFA or BT increased cellulolytic enzyme activity and copies of total bacteria, protozoa, Ruminococcus spp. • Blood FA concentration decreased with BT addition in RPFA- diet but increased with BT addition in RPFA + diet. This study evaluated the effects of betaine (BT) and rumen-protected folic acid (RPFA) on lactation performance, nutrient digestion, rumen fermentation and blood metabolites in dairy cows. Thirty-six mid-lactation Holstein dairy cows were assigned to one of four treatments in a 2 × 2 factorial randomized block design. Supplemental RPFA (0 [RPFA-] or 5.2 mg/kg dietary dry matter [DM] of folic acid [FA] from RPFA [RPFA+]) and BT (0 [BT-] or 4.0 g/kg DM of BT [BT+]) was mixed into the daily ration, respectively. The experiment lasted for 105 days with the first 15 days for adaptation and the following 90 days for sample collection. The RPFA × BT interaction was significant for blood folate concentration which decreased with BT addition in RPFA- diet but increased with BT addition in RPFA + diet. Dry matter intake and body weight change were similar among treatments. Dietary RPFA or BT addition increased yield of milk and milk fat but higher milk protein yield was only observed for RPFA addition. Feed efficiency was increased due to RPFA or BT addition. Apparent total-tract digestibility of DM, organic matter, crude protein, neutral detergent fibre and acid detergent fibre increased with RPFA or BT addition. Ruminal pH decreased with RPFA addition but was unchanged with BT addition. Dietary RPFA or BT addition increased ruminal total volatile fatty acids concentration and altered rumen fermentation mode to more acetate production. Ammonia-N concentration was unchanged with RPFA addition but decreased with BT addition. Addition of RPFA or BT increased activity of carboxymethyl-cellulase, xylanase and protease as well as population of total bacteria, protozoa, Ruminococcus (R.) albus and R. flavefaciens. Population of Prevotella ruminicola was higher for RPFA addition but activity of cellobiase and population of total fungi and Ruminobacter amylophilus was higher for BT addition. Blood concentrations of glucose, non-esterified fatty acid, beta-hydroxybutyrate and homocysteine were similar among treatments. Blood total protein and albumin concentrations were increased with RPFA addition but were not affected by BT addition. The data indicated that addition of RPFA or BT had beneficial impacts on lactation performance, nutrient digestion and ruminal fermentation and BT addition might increase FA utilization efficiency in dairy cows receiving diet without RPFA. [ABSTRACT FROM AUTHOR]

• The higher DM and nutrient intake and average daily gain were observed for folic acid (FA) addition. • Nutrient digestibility, total VFA and microbial population increased with FA and sodium selenite (SS) addition. • Urinary purine derivatives (UPD) increased with FAand SS supplementation. • Digestibility, cellulolytic bacteria and UPD induced by SS addition was greater in diet added without FA than with FA. This study evaluated the effects of folic acid (FA) and sodium selenite (SS) supplements on growth performance, nutrient digestion, ruminal fermentation, microbial enzyme activity, microflora and urinary excretion of purine derivatives (PD) in dairy calves. Thirty-six Holstein calves (63 ± 3.4 days of age and 83 ± 2.1 kg of body weight) were randomly assigned to four treatments in a 2 × 2 factorial arrangement. Two levels of FA (0 or 3.0 mg/kg of FA) and SS (0 or 0.3 mg/kg of Se from SS) were added into diets on a dry matter (DM) basis. Nutrient intake and average daily gain increased with FA addition, but were not affected by SS addition. Both supplements increased total tract digestibility of DM, organic matter and neutral detergent fiber. Ruminal pH and ammonia N concentration decreased, but total volatile fatty acids concentration increased with FA or SS addition. Acetate molar proportion and acetate to propionate ratio increased, while propionate molar proportion decreased with FA addition. The unchanged acetate molar proportion, higher propionate molar proportion and lower acetate to propionate ratio were observed with SS addition compared with the control. Activities of xylanase, pectinase, α-amylase and protease as well as populations of total bacteria, protozoa and methanogens were higher for both supplements compared with the control. Carboxymethyl-cellulase activity and Prevotella ruminicola population increased with FA addition. The Ruminobacter amylophilus population decreased with SS addition. The FA×SS interaction was significant for total tract digestibility of crude protein and acid detergent fiber, populations of total fungi, Ruminococcus (R.) albus, R. flavefaciens, Fibrobacter succinogenes and Butyrivibrio fibrisolvens as well as urinary total PD excretion; these variables increased with SS addition and the increase was greater when the diet was not supplemented with FA than with FA supplemented diet. The results indicated that dietary FA and/or SS addition stimulated nutrient digestion, ruminal fermentation, microbial growth and urinary total PD excretion. [ABSTRACT FROM AUTHOR]