Growth Performance, Nutrient Digestibility, Blood Profiles, and Gut Integrity of Growing Pigs Fed Pickled Fish Residue with Decreased Salt Content

Abstract

This study investigated the growth performance, nutrient digestibility, blood profiles and gut integrity of growing pigs, in response to an increase in pickled freshwater fish residue (PFR) intake following a decrease in salt content. Ninety-six crossbred growing pigs [(Landrace × Large White) × Duroc] with a body weight of 23.65 ± 0.24 kg were randomly assigned to one of four treatments (6 pens/treatment, 4 pigs/pen) in a randomized complete block design. The treatments included: a corn-soybean meal based diet without PFR inclusion (CON) or with PFR addition at 5 (PFR5), 10 (PFR10), and 15% (PFR15), respectively. Desalting via soaking and stirring caused a positive reduction in the salt present on the surface of PFR. Over the 42-day feeding period, an increased level of PFR quadratically increased gain:feed ratio such that gain:feed ratio for PFR10 was greater than that for CON (p < 0.05). Pigs fed PFR10 had greater crude protein digestibility, and lower aspartate aminotransferase and crypt depth than those fed the CON diet (p < 0.05). The linear improvements in crude protein and ether extract digestibility, duodenal villus height, and villus:crypt ratio were observed as the PFR content increased (p < 0.05). However, there were no significant effects on average daily feed intake, dry matter and ash digestibility, blood metabolites (total Ca, P, creatinine, and alkaline phosphatase). Altogether, up to 10% PFR can be included in corn-soybean meal diet without impairing protein digestibility and hepatic enzyme alteration. In fact, administering PFR with lower salt content to growing pigs ultimately promotes their growth performance and gut integrity.