Chito-oligosaccharide as growth promoter replacement for weaned piglets: performance, morphometry, and immune system

The objective of this study was to evaluate the chito-oligosaccharide (COS) against two growth promoter antibiotics, colistin and lincomycin, with respect to growth performance, incidence of diarrhea, visceral characteristics, morphometry, and serum immunoglobulin levels (IgA, IgG, and IgM). A total of 96 Pen Ar Lan (R) piglets (48 barrows and 48 females), weaned at 17 days and with body weight (BW) 5.33 +/- 0.37 kg, were subjected to the evaluation of growth performance and serum. Twenty-four animals, females, 35-day-old and with BW 6.86 +/- 0.64 kg, were used for the assessment of histology and visceral organ weight. The three treatments were a basic diet formulation supplemented with COS (100 mg kg(-1)), colistin (40 mg kg(-1)), or lincomycin (4.4 mg kg(-1)). The antibiotic treatments showed higher average daily gain (ADG) than COS treatment during the period of 49 to 63 days; whereas the feed conversion ratio (FCR) was higher and incidence of diarrhea was lower for the colistin treatment than for other treatments. The spleen weight and the small intestinal length were higher and duodenal pH was lower for COS than for antibiotics. Morphometry indicated greater villus height and higher ratio of villus height to crypt depth with colistin than with COS and a lower lesion score compared with other treatments. The serum IgA concentration was higher for COS in 35-day-old piglets. According to the results, COS was not efficient to replace colistin as a growth promoter for piglets weaned at 17 days; however, the results related to the immune system suggested that COS is a potentially promising product during weaning.