Influence of fermented fish meal supplementation on growth performance, blood metabolites, and fecal microflora of weaning pigs

ABSTRACT This study was conducted to estimate the effect of dietary supplementation with fermented fish meal on growth performance, blood metabolites, and fecal microflora in weaning pigs. A total of 180 weaned pigs ((Landrace ×Yorkshire) × Duroc; with average body weight of 6.0 kg) were randomly distributed among three dietary treatments (0, 0.2, and 0.5% fermented fish meal) in three replicate pens (20 heads per pen) in a completely randomized trial over three weeks. Addition of fermented fish meal to weanling pig diets had a linear effect on average feed intake and a quadratic trend on final body weight, average daily gain, and gain:feed ratio throughout the whole period (but not initial body weight). Hematocrit, monocyte, immunoglobulin G, and blood urea nitrogen levels responded linearly and quadratically with increasing levels of dietary fermented fish meal. Moreover, we found a linear correlation between the diets and lymphocyte and insulin levels among the different dietary treatments. In contrast, red blood cells, white blood cells, hemoglobin, insulin-like growth factor 1, and glucose levels were not affected by diets with different levels of fermented fish. During the experimental period, diets with 0.2% and 0.5% fermented fish meal showed a reduction in Salmonella enterica and Escherichia coli populations (but not E. coli populations at week 3) that were linear, quadratic, or both, compared with controls. In particular, there was a significant reduction in S. enterica population when pigs were fed 0.5% fermented fish meal over the period of 3 weeks). Dietary supplementation with 0.2% and 0.5% fermented fish meal can be used as a protein source to improve growth performance and the parameters chosen for the blood profile, which reduces harmful microorganisms in the feces of weanling pigs.