Dietary inclusion of Orange peels derived pectin and Lactobacillus plantarum for Nile tilapia (Oreochromis niloticus) cultured under indoor biofloc systems

Abstract

A 12-week feeding trial was carried out to investigate possible effects of dietary orange peels derived pectin (OPDP) and <i>Lactobacillus plantarum</i> CR1T5 (LP) singularly or combined on innate immune response, disease resistance, and growth performance of Nile tilapia fingerlings under indoor biofloc system. The fingerlings were fed the following diets: diet 1 (0 g kg⁻¹ OPDP and 0 CFU g⁻¹ <i>L. plantarum</i>), diet 2 (10 g kg⁻¹ OPDP), diet 3 (10⁸ CFU g⁻¹<i>L. plantarum</i>), and diet 4 (10 g kg⁻¹ OPDP +10⁸ CFU g⁻¹<i> L. plantarum</i>). At the end of feeding trial, skin mucus parameters, serum immune parameters, and growth performance were measured. Ten randomly selected fish were used in a challenge test with <i>Streptococcus agalactiae</i>. The results indicated that supplementations of OPDP + LP or/and significantly (<i>P</i> < <i>.05</i>) increased growth performance, skin mucus and serum immunity responses. The highest values were revealed in fish fed both OPDP and LP vs. individual applications. However, no significant (<i>P</i> ><i> .05</i>) differences were observed between fish fed OPDP and LP. The challenge test revealed that the relative percent survival (RSP) in diet 2, diet 3, and diet 4 was 43.33%, 50.0%, and 70.0%, respectively. Among the supplemented groups, fish fed 10 g kg⁻¹ OPDP + LP showed significant (<i>P</i> < <i>.05</i>) higher RPS and resistance to <i>S. agalactiae</i> than the other groups. The present results suggested that the combination of OPDP and LP could be considered as potential feed-additives for aquaculture farmed fish under indoor biofloc system.