Effect of calf starter feeding on gut microbial diversity and expression of genes involved in host immune responses and tight junctions in dairy calves during weaning transition

Abstract

Calf starters are usually offered to dairy calves to facilitate the weaning process, however, the effect of solid feed consumption on gut health has not been well studied. This study aimed to investigate the effect of calf starter feeding on the gut bacterial community and mucosal immune functions in dairy calves during weaning transition. Mucosal tissue and digesta samples were collected from rumen, jejunum, ileum, cecum, and colon upon slaughtering of calves (n=8) after feeding the experimental diets [milk replacer (MR) or milk replacer + calf starter (MR+S)] for 6 wk. Expression of toll-like receptor (TLR) 10 was downregulated along the gut, whereas TLR2 in colon and TLR6 along the gut were upregulated in MR+S-fed calves compared with MR-fed calves. Ileal TLR9 and TLR10 showed higher expression compared with the other regions regardless of the diet. Peptidoglycan recognition protein 1 demonstrated a diet- and gut-regional dependent expression pattern, whereas β-defensin did not. The diet and gut region also affected the expression of tight junction-regulating genes claudin 4 and occludin. Bacterial diversity tended to be different between the 2 diets, whereas the bacterial density was different among gut regions and sample type. The present study revealed that changes in bacterial diversity, expression of genes encoding host mucosal immune responses, and barrier functions were associated with the MR+S diet, and suggests that solid feed consumption may alter gut microbiome and host mucosal functions during weaning transition.

The influence of age and weaning on permeability of the gastrointestinal tract in Holstein bull calves

“…Unfortunately, few studies have evaluated how diet or management strategies affect the regional response of the gastrointestinal tract. Malmuthuge et al (2013) reported that Holstein calves fed a starter ration in combination with milk replacer had greater mRNA expression of claudin-4 in the jejunum and ileum and increased expression of occludin in the jejunum, ileum, and cecum relative to calves fed milk only. The same study suggested that barrier function might be enhanced with consumption of starter intake but these measurements were conducted before weaning.…”

“…It could be expected that these changes may compromise gastrointestinal barrier function (Wijtten et al, 2011) due to low ruminal pH at weaning (Laarman et al, 2012) and that short-term reductions in nutrient provision reduce total-tract barrier function in cattle (Gaebel et al, 1993;Gäbel and Aschenbach, 2002;Zhang et al, 2013). However, only one study known to us has evaluated barrier function in Holstein calves in response to weaning (Malmuthuge et al, 2013). In that study, the mRNA expression of toll-like receptor-2 decreased and the expression of occludin and claudin-4 increased in rumen tissue collected from calves weaned relative to their nonweaned comparatives.…”

Supplementing a yeast probiotic to pre-weaning Holstein calves: Feed intake, growth and fecal biomarkers of gut health

“…In fact, during the first 8 weeks after birth, calves not only experienced an age change, but were also challenged by a diet transition from milk to solid feed (Khan et al, 2016). It has been reported that solid feed consumption altered gut microbiome during weaning transition (Malmuthuge et al, 2013), and the shift of gut microbiomes affected by solid feed could be toward to the mature ruminant state (Meale et al, 2016). By targeting specific bacteria, the current results suggest that the fecal microbial population in dairy calves can be influenced by week of age and weaning, and the natural microbial changes occurring over time in the life of a health calf appears to be more important than the expected SCB effect.…”

Review: Utilization of yeast of Saccharomyces cerevisiae origin in artificially raised calves

“…Recently researchers have demonstrated the importance of introducing starter in calves at an early age. Malmuthuge et al [84] investigated the effect of feeding milk replacer alone or milk replacer with calf starter combined on microbial gut diversity. They were able to show that calf starter in addition to milk replacer resulted in changes in microbial diversity and expression of gene encoding gut barrier function.…”