Effects of yeast culture on performance, gut integrity, and blood cell composition in weanling pigs

¹ Animal Sciences Group, Wageningen University and Research Center, Lelystad, The Netherlands
² Laboratory of Microbiology, Wageningen University and Research Center, Wageningen, The Netherlands
³ Diamond V Mills, Inc., Cedar Rapids, IA

^* To whom correspondence should be addressed. E-mail: carola.vanderpeet{at}wur.nl.

	Abstract

An experiment was conducted to determine effects of yeast culture (YC) and modified yeast culture [YC + cell wall product (CWP) containing mannan oligosaccharides (MOS)] in pig diets on performance, gut integrity, and blood cell composition in weanling pigs and to determine whether these dietary supplements can replace antimicrobial growth promoters (AGP) in pig diets. A total of 480 weanling pigs (27-d old and 7.8 ± 0.1 kg) were assigned to 1 of 4 experimental treatments: 1) diets without AGP or YC (control diet); 2) control + AGP; 3) control + 0.125% YC; 4) control + 0.125% YC + 0.2% CWP. Piglets were fed experimental diets for 5 wk after weaning. Blood samples were collected from 8 piglets at weaning and from 8 piglets per treatment on d 14 and 35 after weaning, for blood cell composition. These piglets were slaughtered for measurement of villous length and crypt depth in the jejunal mucosa and microbial profiling on the intestinal digesta. Average daily gain (P = 0.06) and G:F (P = 0.02) were improved for piglets that were fed the supplemented diets compared to piglets that were fed the control diet. Average daily feed intake was unaffected by dietary treatment. Performance was similar in piglets fed diets supplemented with AGP, YC, and YC + CWP. Blood cell composition, villous length, crypt depth, and microbial composition in the gut were unaffected by dietary treatment but they were affected by time after weaning. Red blood cells, hemoglobin, hematocrit value, mean cell volume, mean cell hemoglobin, percentage of lymphocytes in the leukocyte population, villous length, and crypt depth were greater (P < 0.05) at 5 wk after weaning than at 2 wk after weaning. Eosinophils (P = 0.06) in the leukocyte population tended to be greater at 5 wk after weaning. Concentration of neutrophils in the leukocyte population and the percentage of CD4 and CD8 cells were lower (P < 0.02) at 5 wk after weaning. The CD4/CD8 ratio (P = 0.07) tended to be lower at 5 wk after weaning. Results suggest that yeast culture could be an alternative to AGP in diets for weanling pigs and addition of CWP to diets containing YC will not improve performance or health of weanling pigs above that of YC alone. More insight into the mode of action of YC is needed.

Key Words: gut integrity, blood cell composition, performance, weanling pigs, yeast culture