Jiakun Wang

Effects of Supplemental Levels of Saccharomyces cerevisiae Fermentation Product on Lactation Performance in Dairy Cows under Heat Stress.

The objectives of this study were to evaluate the effects of different supplemental levels of Saccharomyces cerevisiae fermentation product (SCFP; Original XP; Diamond V) on lactation performance in Holstein dairy cows under heat stress. Eighty-one multiparous Holstein dairy cows were divided into 27 blocks of 3 cows each based on milk yield (23.6±0.20 kg/d), parity (2.88±0.91) and day in milk (204±46 d). The cows were randomly assigned within blocks to one of three treatments: 0 (control), 120, or 240 g/d of SCFP mixed with 240, 120, or 0 g of corn meal, respectively. The experiment was carried out during the summer season of 2014, starting from 14 July 2014 and lasting for 9 weeks with the first week as adaption period. During the experimental period, average daily temperature-humidity index (measured at 08:00, 14:00, and 20:00) was above 68, indicating that cows were exposed to heat stress throughout the study. Rectal temperatures tended to decrease linearly (p = 0.07) for cows supplemented with SCFP compared to the control cows at 14:30, but were not different at 06:30 (p>0.10). Dry matter intake was not affected by SCFP supplementation (p>0.10). Milk yield increased linearly (p<0.05) with increasing levels of SCFP. Feed efficiency (milk yield/dry matter intake) was highest (p<0.05) for cows fed 240 g/d SCFP. Cows supplemented with SCFP gained (p<0.01) body weight, while cows in the control lost body weight. Net energy balance also increased linearly (p<0.01) with increasing levels of SCFP. Concentrations of milk urea nitrogen (p<0.01) decreased linearly with increasing levels of SCFP, while no difference (p>0.10) was observed among the treatments in conversion of dietary crude protein to milk protein yield. In summary, supplementation of SCFP alleviated the negative effect of heat stress in lactating Holstein dairy cows and allowed cows to maintain higher milk production, feed efficiency and net energy balance. Effects of SCFP were dose-dependent and greater effects were observed from higher doses.

Effects of tea seed saponin supplementation on physiological changes associated with blood methane concentration in tropical Brahman cattle

A 59-day experiment compared the effects of increasing tea seed (Camellia sinensis L.) saponin (TSS) supplementation on dry matter intake (DMI), liveweight (LW), rumen fermentation, methanogenesis, blood biochemistry and animal tolerance. Six, 10, 15, 20, 25 and 30 g of powder TSS were dissolved during 5, 7, 4, 3, 3 and 2 days, respectively, and infused into the rumen of four rumen-cannulated Brahman steers (234 ± 13.6 kg LW; least-squares means ± s.e.m.) or mixed in the basal diet [BD: 0.15 Rhodes grass (Chloris gayana) hay plus a high-grain feed (0.85)] of two non-cannulated (253 ± 19.3 kg) steers. Overall, DMI was not affected, by the sequential infusion of TSS (5.3 ± 0.15 kg) or addition to the BD (5.4 ± 0.18 kg), but relative to all diets, 6 g of TSS supplementation reduced DMI (P < 0.05), while the administration above 30 g of the supplement was associated with significantly (P < 0.001) reduced DMI, scours and bloat disorders. Clinical symptoms disappeared 8 days after withdrawal of the supplement. LW increased with time (P < 0.05) and the final LW was similar for cannulated (258 ± 13.6 kg) and non-cannulated (276 ± 19.3 kg) steers. Saponin supplementation reduced total volatile fatty acid (VFA) concentration (P < 0.05), modified pattern of individual molar VFA concentrations and moderately increased ruminal pH (P < 0.05). Cannulated and non-cannulated steers fed the BD had similar daily (g) methane or yield (CH4 g/kg DMI) emissions while in respiratory chambers. However, compared with cannulated (8.0 ± 1.20 ng/mL) animals, the addition of 30 g of TSS in the BD increased (P < 0.01) blood CH4 concentration in non-cannulated (15.6 ± 1.74 ng/mL) animals. Diets supplemented with 30 g of TSS were associated with higher chloride (P < 0.01) and alkaline phosphatase (P < 0.05) blood concentrations, and lower serum concentrations of potassium and urea nitrogen (P < 0.01), iron and total lipase (P < 0.05), than was the BD. It was concluded that higher levels of TSS supplement may evoke physiological changes in the animal. However, the potential CH4 mitigation effect of this form of saponin in tropical cattle needs further investigation, alongside the derived response of the rumen microbial ecology to the tested range of supplementation.

Comparative Analysis of the Microbiota Between Sheep Rumen and Rabbit Cecum Provides New Insight Into Their Differential Methane Production

The rumen and the hindgut represent two different fermentation organs in herbivorous mammals, with the former producing much more methane than the latter. The objective of this study was to elucidate the microbial underpinning of such differential methane outputs between these two digestive organs. Methane production was measured from 5 adult sheep and 15 adult rabbits, both of which were placed in open-circuit respiratory chambers and fed the same diet (alfalfa hay). The sheep produced more methane than the rabbits per unit of metabolic body weight, digestible neutral detergent fiber, and acid detergent fiber. pH in the sheep rumen was more than 1 unit higher than that in the rabbit cecum. The acetate to propionate ratio in the rabbit cecum was more than threefold greater than that in the sheep rumen. Comparative analysis of 16S rRNA gene amplicon libraries revealed distinct microbiota between the rumen of sheep and the cecum of rabbits. Hydrogen-producing fibrolytic bacteria, especially Butyrivibrio, Succiniclastium, Mogibacterium, Prevotella, and Christensenellaceae, were more predominant in the sheep rumen, whereas non-hydrogen producing fibrolytic bacteria, such as Bacteroides, were more predominant in the rabbit cecum. The rabbit cecum had a greater predominance of acetogens, such as those in the genus Blautia, order Clostridiales, and family Ruminococcaceae. The differences in the occurrence of hydrogen-metabolizing bacteria probably explain much of the differential methane outputs from the rumen and the cecum. Future research using metatranscriptomics and metabolomics shall help confirm this premise and understand the factors that shape the differential microbiota between the two digestive organs. Furthermore, our present study strongly suggests the presence of new fibrolytic bacteria in the rabbit cecum, which may explain the stronger fibrolytic activities therein.

Effects of Saccharomyces cerevisiae fermentation products on performance and rumen fermentation and microbiota in dairy cows fed a diet containing low quality forage

BackgroundA possible option to meet the increased demand of forage for dairy industry is to use the agricultural by-products, such as corn stover. However, nutritional value of crop residues is low and we have been seeking technologies to improve the value. A feeding trial was performed to evaluate the effects of four levels of Saccharomyces cerevisiae fermentation product (SCFP; Original XP; Diamond V) on lactation performance and rumen fermentation in mid-lactation Holstein dairy cows fed a diet containing low-quality forage. Eighty dairy cows were randomly assigned into one of four treatments: basal diet supplemented with 0, 60, 120, or 180 g/d of SCFP per head mixed with 180, 120, 60, or 0 g of corn meal, respectively. The experiment lasted for 10 wks, with the first 2 weeks for adaptation.ResultsDry matter intake was found to be similar (P > 0.05) among the treatments. There was an increasing trend in milk production (linear, P ≤ 0.10) with the increasing level of SCFP supplementation, with no effects on contents of milk components (P > 0.05). Supplementation of SCFP linearly increased (P < 0.05) the N conversion, without affecting rumen pH and ammonia-N (P > 0.05). Increasing level of SCFP linearly increased (P < 0.05) concentrations of ruminal total volatile fatty acids, acetate, propionate, and butyrate, with no difference in molar proportion of individual acids (P > 0.05). The population of fungi and certain cellulolytic bacteria (Ruminococcus albus, R. flavefaciens and Fibrobacter succinogenes) increased linearly (P < 0.05) but those of lactate-utilizing (Selenomonas ruminantium and Megasphaera elsdenii) and lactate-producing bacteria (Streptococcus bovis) decreased linearly (P ≤ 0.01) with increasing level of SCFP. The urinary purine derivatives increased linearly (P < 0.05) in response to SCFP supplementation, indicating that SCFP supplementation may benefit for microbial protein synthesis in the rumen.ConclusionsThe SCFP supplementation was effective in maintaining milk persistency of mid-lactation cows receiving diets containing low-quality forage. The beneficial effect of SCFP could be attributed to improved rumen function; 1) microbial population shift toward greater rumen fermentation efficiency indicated by higher rumen fungi and cellulolytic bacteria and lower lactate producing bacteria, and 2) rumen microbial fermentation toward greater supply of energy and protein indicated by greater ruminal VFA concentration and increased N conversion. Effects of SCFP were dose-depended and greater effects being observed with higher levels of supplementation and the effect was more noticeable during the high THI environment.

Effects of Replacement of Concentrate Mixture by Broccoli Byproducts on Lactating Performance in Dairy Cows

The objective of the present study was to determine the effects of feeding pelletized broccoli byproducts (PBB) on milk yield and milk composition in dairy cows. In Trial 1, an in vitro gas test determined the optimal replacement level of PBB in a concentrate mixture in a mixed substrate with Chinese wild ryegrass hay (50:50, w/w) at levels of 0, 10%, 20%, 30%, or 40% (dry matter basis). When the concentrate was replaced by PBB at a level of 20%, no adverse effects were found on the gas volume or its rate constant during ruminal fermentation. In trial 2, 24 lactating cows (days in milk = 170.4±35; milk yield = 30±3 kg/d; body weight = 580 ±13 kg) were divided into 12 blocks based on day in milk and milk yield and randomly allocated to two dietary treatments: a basic diet with or without PBB replacing 20% of the concentrate mixture. The feeding trial lasted for 56 days; the first week allowed for adaptation to the diet. The milk composition was analyzed once a week. No significant difference in milk yield was observed between the two groups (23.5 vs 24.2 kg). A significant increase was found in milk fat content in the PBB group (p<0.05). Inclusion of PBB did not affect milk protein, lactose, total solids or solids-not-fat (p>0.05). These results indicated that PBB could be included in dairy cattle diets at a suitable level to replace concentrate mixture without any adverse effects on dairy performance.

Persistence of cellulolytic bacteria Fibrobacter and Treponema after short-term corn stover-based dietary intervention reveals the potential to improve rumen fibrolytic function

Limited lignocellulose degradation is the primary obstacle to feed digestion efficiency in ruminant animals. Low-quality forage with high levels of fibrous components can favor the proliferation of fibrolytic bacteria, but whether this can result a profound microbial shift after dietary intervention remains unclear. In this study, we monitored the microbial communities in the rumens of five ruminally cannulated Hu sheep through dietary transition from alfalfa hay (AH, pre-CS) to corn stover (CS, post-CS) and then back to AH (post-AH), with each treatment lasting for 14 days. The CS intervention significantly increased the relative abundance of microorganisms involved in lignocellulose degradation, including Fibrobacter and Treponema. When the diet was switched back to AH, the microbial community did not completely return to a pre-CS treatment state. In the post-AH microbial community, the relative abundances of Fibrobacter and Treponema were persistently high, and were similar to those in the post-CS community. Meanwhile, the diversity of the microbial community increased after dietary transition from AH to CS and remained significantly higher after transition from CS to AH compared to those under the original AH diet. Enzyme activity measurement verified significant increase of carboxymethyl cellulase (CMCase) and xylanase catalytic activities in the rumen. Microbial functional predictions using Tax4Fun revealed that this microbial persistence may enhance the carbohydrate metabolism pathway in the rumen. In summary, persistence of Fibrobacter and Treponema can be enhanced through a low-quality forage intervention at least for 2 weeks, which may enlighten the reprogram of microbial population in the rumen in the future.