Effect of probiotic Bacillus amyloliquefaciens strain H57 on productivity and the incidence of diarrhoea in dairy calves

Abstract

A spore-forming probiotic, Bacillus amyloliquefaciens strain H57 (H57), was administered to dairy calves in starter pellets to determine effects on liveweight gain, feed conversion efficiency and animal health under summer feeding conditions, without antibiotics. Twenty-four male and female calves were allocated into two groups and from 4 weeks of age individually offered 6 L/day of whole milk and ad libitum starter pellets impregnated with H57 (3.16 × 108 cfu per kg DM) or without (Control) until 12 weeks of age. The calves were housed in a non-air-conditioned animal house, with deep-straw bedding over concrete, under typically challenging subtropical summer conditions. After 12 weeks the calves were released into a grazing paddock as one group and were supplemented ad libitum with control pellets and hay, until 19 weeks of age. From Weeks 4 to 12, liveweight and feed intakes were measured weekly and health status was monitored daily. Rumen fluid and blood were collected at Weeks 4 and 12, and to test for persistence after cessation of feeding H57, each were measured again at Week 19. From Weeks 4 to 12, the H57 calves grew faster (767 vs 551 g/day, P = 0.01), tended to consume more pellets (1013 vs 740 g DM/day, P = 0.07) and were 19% more feed conversion efficiency (2.43 vs 2.90 kg milk + starter DM/kg weight gain, P = 0.01) compared with the Control calves. The mean duration of each diarrhoea event was 2 days less for the H57 calves than the Control (P = 0.01). The H57 calves weaned 9 days earlier (P = 0.02) and were heavier at Week 19 (155 vs 139 kg, P = 0.03) than the Control calves. The only effect of H57 on rumen volatile fatty acid concentrations was an elevation in valerate at Week 12 (4.10 vs 2.47 mmol/L, P = 0.03). Plasma β-hydroxy butyrate was also elevated in the H57 calves at Week 19 (0.24 vs 0.20 mmol/L), indicating the potential of H57 to improve rumen development. H57 can be used to improve the nutritional performance and reduce the risk of diarrhoea in dairy calves as they transition from milk to dry feed.

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

“…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. Not only was there a 39% increase in live weight gain, a 16.2% increase in feed conversion efficiency and a reduction in weaning age by nine days, but the H57 fed calves also had a reduction in the occurrence and duration of diarrhoea.…”

“…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).…”

“…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.…”

“…by Le et al (2016b) and Le et al (2016a). The use of these animals and experimental procedures were approved by the Animal Ethics Committee of the University of Queensland under the approval numbers of SVS/022/13/ARC and SVS/280/14/ARC for the sheep and calves respectively.…”

“…The calves were randomly divided into two treatment groups (control and H57). From 24 h after birth until four weeks of age the calves were separated from their dams and fed whole milk by a robotic milk feeder (maximum five feeding times/day and maximum 2 L each feed) and ad libitum sorghum-based, starter concentrate pellets that were antibiotic free (Le et al, 2016a). From 4 to 12 weeks of age the calves were fed 6 L of whole milk per day and ad libitum starter pellets.…”