Production responses of reproducing ewes to a by-product-based diet inoculated with the probiotic Bacillus amyloliquefaciens strain H57

Abstract

The potential application of the spore-forming probiotic Bacillus amyloliquefaciens strain H57 (H57) as a novel probiotic for ruminants was evaluated in reproducing ewes. Performance responses were determined by delivering H57 in a pelleted diet based mainly on palm kernel meal (PKM) and sorghum grain. PKM is an agro-industrial by-product with a reputation for poor palatability and the availability of the starch in sorghum grain can be limited in ruminants. The hypothesis was that H57 improves the feeding value of a relatively low quality concentrate diet. Twenty-four first-parity white Dorper ewes were fed PKM-based pellets manufactured with or without H57 (109 cfu/kg pellet) in late pregnancy. During this phase of late pregnancy, the H57 ewes ate 17% more dry matter (1019 vs 874 g/day, P = 0.03), gained more weight (194 vs 30 g/day, P = 0.008) and retained more nitrogen (6.13 vs 3.34 g/day, P = 0.01), but produced lambs with a similar birthweight (4.1 vs 4.2 kg, P = 0.73). Rumen fluid collected from H57 ewes in late pregnancy had higher pH (7.1 vs 6.8, P = 0.07), acetate : propionate ratio (3.4 vs 2.7, P = 0.04), lower ammonia (69 vs 147 mmol/L, P = 0.001) and total volatile fatty acid concentrations (40 vs 61 mg/L, P = 0.02). The digestibility of dry matter, organic matter and fibre were similar between the two groups. The lambs of the H57 ewes grew faster than those of the Control ewes for the first 21 days of lactation (349 vs 272 g/day, P = 0.03), but not thereafter. H57 can improve feed intake and maternal liveweight gain in late pregnancy of first-parity ewes fed a diet based on PKM.

Microbial Community Structure and Functionality in Ruminants Fed the Probiotic Bacillus amyloliquefaciens H57

“…This could lead to the increased weight gain observed in the H57 fed sheep. The H57 fed sheep also showed an overall increased expression of enzymes involved in glycolysis, suggesting an increased conversion of sugars into energy substrates such as VFAs.However, as Le et al (2016b) observed, total VFA concentration was not higher in the H57 fed sheep, but in fact was significantly lower (P = 0.02) than the control ewes.The findings of this study suggest that the addition of H57 to pelleted feed stimulates rumen microbial populations to express greater quantities of hemicellulolytic and glycolysis pathway enzymes, compared to those in animals fed the control feed. As the feed is more efficiently digested, the host is able to utilise the resultant energy substrates for growth and development.…”

“…However, as Le et al (2016b) observed, total VFA concentration was not higher in the H57 fed sheep, but in fact was significantly lower (P = 0.02) than the control ewes.…”

“…To conclude, the methodology adopted was an effective means of cultivating B. amyloliquefaciens H57 to produce inoculant in sufficient quantities for several tonnes of animal feed at greater than 10 9 cfu kg -1 (Le et al, 2016a;Le et al, 2016b). Inoculum prepared in this manner has been stored for more than a year without loss of viability (Table S2.5).…”

“…Ewes fed grass-clover hay inoculated with HayRite™, a composite probiotic inoculum comprised of B. amyloliquefaciens strains H57 and H60, ate more hay, digested it better, had more weight gain and retained more nitrogen, than ewes fed uninoculated hay . Le et al (2016b), showed that pregnant Dorper ewes fed a poor quality concentrate diet supplemented with H57 at 10 9 cfu kg -1 pellets, had a significant increased weight gain (P = 0.008) coupled with an increase in uptake of dry matter (P = 0.03) and increased nitrogen retention (P = 0.01) compared to the control animals given pellets without H57. The beneficial effect of H57 was also demonstrated in dairy calves (Le et al, 2016a) fed sorghum based concentrate pellets with and without H57 as they weaned.…”

“…A number of probiotics have demonstrated an ability to benefit ruminants, although the mode of action and the impact the probiotic has on the rumen microbiome, is not always known. The bacterium B. amyloliquefaciens H57 is one such example of a probiotic that has demonstrated a positive influence on weight gain and nitrogen retention in sheep and cattle Le et al, 2016a;Le et al, 2016b). The primary objective of my research aims to develop an understanding of how H57 is able to benefit these animals.…”