Finer grinding yeast supplements may boost broiler immunity, gut health

Using a more finely ground yeast cell wall (YCW) feed supplement may boost immune functioning and gut health in broilers. 

A team of Chinese researchers sought to understand the influence of yeast cell wall powder and particle size in broiler diets. The group looked at responses to the use of different particle size for the supplement because that interaction has not been examined.

The group focused on the effect that fine grinding the supplement could have on growth performance, serum metabolites, antioxidant status and immunity in broilers.

“Birds fed diet supplemented with fine rather than coarse grinding YCW showed increased secretion of intestinal SIgA [secretory immunoglobulin A] and IgG [immunoglobulin G], enhanced T-SOD [total superoxide dismutase] activity, and reduced MDA [malondialdehyde] accumulation in the ileal mucosa,”​ said researchers. “Therefore, the capacity to improve immune function and intestinal oxidative status of broilers was more pronounced in fine grinding YCW.”​

Why particle size​

Yeast components are known to enhance immunity and protect against negative microorganisms (Shashidhara and Devegowda, 2003 and Ganner and Schatzmayr, 2012), said reseachers.

Past studies have demonstrated the potential positive influence of β-glucans, a feature of YCW, on the immune system, they said. Previous research also has raised the possibility that YCW supplements may boost growth performance, improve intestinal morphology and promote organ development.

Previous work with particle size has demonstrated that it can alter bio-accessibility, they said.

“In broilers, Zhang et al. (2009) also found that efficacy of ginger root (Zingiber officinale) was mediated by its particle size, and the ability to improve antioxidant status was more pronounced in fine grinding ginger,”​ said researchers.

However, little is known about what effect fine-grinding YCW would have on broiler production, they said.

“We hypothesized that YCW under fine grinding treatment would exhibit a higher bioavailability than its counterpart under coarse grinding process in vivo,” ​they said. ​

Experiment details​

For the tests, 144 broiler chicks were given one of three experimental diets and split into six replicates, said researchers. The diets included a basal control diet predominantly comprised of corn and soybean meal and oil, and that diet with either 1g/kg coarse or finely ground YCW powder.

Birds were fed for 42 days, they said. The YCW powder used came from the Nanjing Nature Biotech Co.

Birds were weighed on days 21 and 42 and feed intake was recorded, said researchers. Average daily feed intake (ADFI), average daily gain (ADG) and the feed conversion ratio (FCR) were determined.

Blood samples were collected from selected birds on days 21 and 42, they said. Cecum samples and the bursa, thymus and spleen were collected and salmonella​ and E. coli​ colonies were determined.

Contents of the jejunal and ileal segments were collected along with the mucosa, they said.

Results ​

None of the treatments had a significant influence on broiler growth performance, said researchers. The unchanged growth performance could be related to the low amount of supplement included in the diets or the strain of yeast used.

Different intestinal and immune reactions were seen, they said.

The inclusion of either form of YCW powder increased the levels of total cholesterol in serum and bursa weight at the end of the experiment, they said. But levels of other biochemicals like glucose, triglyceride and total protein, along with the weight of the spleen and thymus, were not affected.

“YCW powder increased serum cholesterol content, indicating that YCW may alter circulatory cholesterol metabolism,” ​said the scientists. “However, in the present study, no clear explanation could be given for the change of cholesterol concentration.”​

Test diets tended to reduce the amount of E. coli​ colonies present in cecal content at day 42, they said. But no change was seen with Salmonella​.

Birds getting the finely ground supplement saw boosted ileal SIgA levels and IgG amounts by day 21, they said.

“Birds fed diets containing fine grinding YCW showed increased ileal T-SOD activity at 21 day whereas decreased MDA content at 42 day, respectively,” ​they said. “Neither ileal T-SOD activity nor MDA content was affected by coarse YCW powder.”​

“The present study demonstrated that fine rather than coarse grinding YCW promoted ileal SIgA and IgG secretion, indicating that fine grinding YCW can improve ileal immune status and the bioavailability of YCW can be increased by reducing its particle size,” ​they said.​