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Highlights • Ruminal fermentation was improved with coated folic acid (CFA) supplementation, but depressed by soybean oil (SO) supplementation. • Microbial cellulolytic enzyme activities and ruminal NDF degradability increased with supplementary CFA, but decreased with SO supplementation. • The growth of cellulolytic bacteria was promoted by supplementary CFA, but depressed by SO supplementation. • Urinary excretion of purine derivatives increased with CFA, but decreased with SO supplementation. • CFA + SO interacted: CFA reduced the negative effects of SO on ruminal fermentation. Abstract This study was conducted to evaluate the effects of dietary soybean oil (SO) and coated folic acid (CFA) supplementation on ruminal digestion kinetics, fermentation, microbial enzyme activity and bacterial abundance in Jinnan beef steers. Eight ruminally cannulated Jinnan beef steers, averaging 15 months of age and 415 ± 5.6 kg of body weight (BW; Mean ± S.E.), were used in a replicated 4 × 4 Latin square design by a 2 × 2 factorial arrangement. Two levels of CFA (0 mg [FA-] or 115 mg per kg dietary DM [FA + ]) were supplemented to the diets without or with SO supplementation (0 g [SO−] or 30 g per kg dietary dry matter [DM] [SO + ]). Steers were fed a total mixed ration with ensiled corn forage to concentrate ratio of 50:50 on a DM basis. The SO × CFA interaction was observed for ruminal pH, total VFA concentration, molar proportions of acetate and propionate, the ratio of acetate to propionate and ammonia N content. Ruminal pH increased with SO supplementation, but decreased with CFA supplementation. Ruminal total VFA concentration, acetate molar proportion and acetate to propionate ratio decreased with SO supplementation, but increased with CFA supplementation. Ruminal ammonia-N content decreased with SO or CFA supplementation. No SO × CFA interaction was observed for nutrient degradability and digestibility. Degradability of neutral detergent fibre (NDF) and digestibility of DM, organic matter, NDF and acid detergent fibre decreased with SO supplementation, but increased with CFA supplementation. Degradability and digestibility of crude protein was not affected by SO supplementation, but increased with CFA supplementation. Pectinase activity was unaltered, whereas, other microbial enzyme activity, bacterial abundance and total PD excretion were affected by SO × CFA interaction. Activities of carboxymethyl-cellulase, cellobiase and xylanase and abundance of R. albus, R. flavefaciens, F. succinogenes and B. fibrisolvens decreased with SO supplementation, but increased with CFA supplementation. Activities of pectinase, α-amylase and protease as well as total bacterial abundance were not affected by SO supplementation, but increased with CFA supplementation. Total protozoal abundance decreased with SO supplementation, but was not affected by CFA supplementation. Abundance of P. ruminicola and R. amylophilus increased with SO or CFA supplementation. Total PD excretion increased with CFA supplementation, but decreased with SO supplementation. The results suggested that ruminal fermentation, NDF degradability, protozoal abundance, cellulolytic bacterial abundance and enzyme activity decreased with dietary SO supplementation, but increased with CFA supplementation. The supplementation of CFA in the SO diet could relieve the negative effects of SO on ruminal fermentation. [ABSTRACT FROM AUTHOR]

This experiment was to evaluate the effects of rumen-protected pantothenate (RPP) on ruminal fermentation, microbial enzyme activity, bacteria population and urinary excretion of purine derivatives in growing beef steers. Eight ruminally cannulated first-generation crossbred (Blonde d′Aquitaine × Simmental) beef steers, averaging 12 months of age and 363 ± 7 kg of body weight (BW), were allocated into a replicated 4 × 4 Latin square design. Four treatments were control, low-RPP (LRPP), medium-RPP (MRPP) and high-RPP (HRPP) with 0, 0.32, 0.48 and 0.64 g RPP per kg dietary DM, respectively. Steers were fed a total mixed ration and dietary concentrate to corn silage ratio was 50:50 based on a dry matter (DM) basis. The experiment included four periods and lasted for 96 days, each period contained 14 days of adaptation and 10 days of data collection. Ruminal pH decreased linearly with increasing RPP supplementation and was lower for MRPP than for control. Ruminal total VFA concentration increased linearly with increasing RPP supplementation and was higher for MRPP than for control. The acetate to propionate ratio increased linearly due to the unchanged acetate molar proportion and the tendency towards decreased propionate proportion. Ruminal DM and neutral detergent fibre degradability of corn silage increased quadratically, whereas DM and crude protein degradability of concentrate mix increased linearly with increasing RPP supplementation. Activities of carboxymethyl-cellulase, cellobiase, xylanase and α-amylase increased linearly and was higher for MRPP than for control. Populations of R. albus, R. flavefaciens, F. succinogenes, B. fibrisolvens, P. ruminicola and R. amylophilus increased linearly and quadratically with increasing RPP supplementation. Urinary excretion of purine derivatives increased linearly with increasing RPP supplementation and was higher for HRPP and MRPP than for LRPP and control. The results indicated that dietary supplementary RPP improved ruminal fermentation, in situ ruminal degradation and urinary excretion of purine derivatives by stimulating bacteria growth and microbial enzymes secretion. It is suggested that supplementary RPP regulated bacteria growth and microbial enzymes secretion in a dose-dependent manner. Under the current experimental condition, the appropriate dose of RPP was at 0.48 g per dietary DM for growing crossbred beef steer. [ABSTRACT FROM AUTHOR]

• Coated zinc sulfate (CZS) could be used as a Zn supplement in dairy cows. • Supplementing 20 or 30 mg Zn/kg DM as CZS in diets containing 31.2 mg Zn/kg DM stimulated lactation performance and rumen fermentation in cows. • Dietary Zn was required for rumen microbial growth and enzyme activity. This study was to evaluate impacts of zinc sulfate (ZS) and coated ZS (CZS) supplementation on milk performance, nutrient digestibility and rumen fermentation. Forty-five Holstein dairy cows were assigned in a randomized block design to one of five treatments: control, ZS supplementation (30 mg Zn/kg dry matter [DM] as ZS) or CZS supplementation (10, 20 and 30 mg Zn/kg DM as CZS for LCZS, MCZS and HCZS, respectively). The experiment lasted for 110 days with 20 days for adaptation and 90 days for data collection. When comparing Zn source at same supplemental level (30 mg Zn/kg DM), milk yield and total-tract digestibility of neutral detergent fibre (NDF) and acid detergent fibre (ADF) tended to be higher and ruminal activities of xylanase, cellobiase, pectinase and protease and serum alkaline phosphatase (ALP) were higher for HCZS than for ZS. Increasing CZS addition linearly increased DM intake and yields of milk, milk fat and milk protein but did not affect milk lactose yield, milk composition content and feed efficiency. Digestibility of DM, organic matter, crude protein, NDF and ADF, ruminal total volatile fatty acids content and acetate to propionate ratio linearly increased but ammonia N content linearly decreased with increasing CZS addition. Quadratic responses were observed for proportions of acetate and propionate. Activities of cellulase and protease and populations of total bacteria, fungi, protozoa, dominant cellulolytic and amylolytic (proteolytic) bacteria responded linearly and positively with increasing CZS addition. Increasing CZS addition linearly increased liver Zn and blood total protein, albumin, ALP and Zn. Results indicated that CZS could be used as a Zn supplement in cows, and supplementing 20 or 30 mg/kg DM of Zn from CZS stimulated performance, nutrients digestion and ruminal fermentation and improved Zn status in cows fed diets containing 31.2 mg Zn/kg DM. [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]