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Rainbow trout silage as immune stimulant and feed ingredient in diets for M ozambique tilapia ( O reochromis mossambicus )
Author(s) -
Goosen Neill Jurgens,
Wet Lourens Francois,
Görgens Johann Ferdinand
Publication year - 2016
Publication title -
aquaculture research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.646
H-Index - 89
eISSN - 1365-2109
pISSN - 1355-557X
DOI - 10.1111/are.12497
Subject(s) - silage , tilapia , biology , formic acid , food science , oreochromis mossambicus , ingredient , rainbow trout , zoology , biochemistry , fish <actinopterygii> , fishery
Abstract Peptides and free amino acids resulting from protein hydrolysis could act as stimulants of fish non‐specific immunity. The study aimed to determine the potential of rainbow trout viscera silage as immune stimulant and feed ingredient for M ozambique tilapia, and to establish whether formic acid used during silage preparation contributed to any effects. Four diets were evaluated: a reference diet (R), one containing 6.5 g kg −1 formic acid ( FA ) and two silage diets containing 160 g kg −1 ( SL , low inclusion) and 285 g kg −1 ( SH , high inclusion) silage. Low silage inclusion improved phagocytic activity of leucocytes compared with the reference, while high inclusion showed no improvement. No other non‐specific immunity parameters or haematology were affected by any treatments. High silage inclusion significantly decreased growth and led to higher mortality, while formic acid had no effect on growth. It is concluded that rainbow trout viscera silage can stimulate the cellular non‐specific immunity of O reochromis mossambicus , and that protein hydrolysis products (and not formic acid) is responsible for the stimulation. The silage can also serve as source of dietary protein and essential amino acids in tilapia diets. However, both fish growth performance and improvement in cellular immunity are dependent on silage inclusion level.