The influence of dietary fish oil replacement with mixture of vegetable oils on reproductive performance, immune responses and dynamic of fatty acids during embryogenesis in Oncorhynchus mykiss

Abstract

A 90‐day feeding trial was carried out to examine the influence of fish oil (FO) substitution with blends of vegetable oils (VOs) on reproductive efficiency of female brooders and fluctuation in fatty acid (FA) profile of embryos in Oncorhynchus mykiss. A basal diet was formulated in which 20% (80FO/20VO), 50% (50FO/50VO), 75% (25FO/75VO) and 100% (100VO) of FO were replaced by mixture of VO. Reproductive performance of brooders was not affected by drastic alternations in FA profile of diets. The level of saturated and monounsaturated FAs (MUFAs) significantly increased, whereas the levels of long‐chain polyunsaturated FAs (LC‐PUFAs), mainly docosahexaenoic acid, profoundly decreased during embryogenesis. The concentrations of MUFA and n−6 PUFA increased in the eggs with increasing the incorporation of VO mixture in diets; however, the concentration of LC‐PUFA and n−3/n−6 PUFA ratio decreased. Haematological parameters and humoral immune responses including total immunoglobulin content, lysozyme and alternative complement pathway activities in brooders fed with the experimental diets did not statically different. In summary, incorporating mixture of various VO sources especially linseed and sunflower oils as good sources of α‐linolenic and linoleic acids, respectively, along with low levels of residual fat from fish meal in diet suggested a good strategy for providing the appropriate essential FA requirements of O. mykiss brooders for their successful reproduction.

Enhancing Reproductive Performance of Freshwater Finfish Species through Dietary Lipids

“…Lipids and various classes of fatty acids (FA) provide the energy required by broodstock during gonadogenesis and embryogenesis and are regarded as crucial components of cell structures and organelles during organ development [63]. Fatty acid requirements during gonadogenesis and larval development are dictated by the individual levels of each dietary FA and relative proportions of the FA main classes, which can have a significant impact on reproduction success [63][64][65]. Lipid manipulation in broodstock diets of several fish species has proven to be effective in promoting reproductive performance.…”

“…Dietary lipids, which comprise fats and oils (triglycerides), are used by fish as a source of metabolic energy, stress resistance, immune development, hormone precursors, and essential fatty acid (EFA) sources [ 19 , 62 ]. Lipids and various classes of fatty acids (FA) provide the energy required by broodstock during gonadogenesis and embryogenesis and are regarded as crucial components of cell structures and organelles during organ development [ 63 ]. Fatty acid requirements during gonadogenesis and larval development are dictated by the individual levels of each dietary FA and relative proportions of the FA main classes, which can have a significant impact on reproduction success [ 63 – 65 ].…”

Dietary Lipid Supplementation Could Significantly Affect the Growth, Fatty Acid Profiles, and Expression of PPARα, Leptin, and Adiponectin Genes in Juvenile Genetically Improved Farmed Tilapia

“…Condition factor (CF, %) = 100 × W f /(L f ) 3 ; Protein efficiency ratio (PER, %) = 100 × (W f − W i )/W p ;…”

“…Lipid is an essential nutrient, which plays an important physiological role on maintaining the normal function, promoting growth, development, and reproduction and improving survival rate (SR) of fish. [ 1–3 ] Dietary lipid is a source of energy and essential fatty acids. [ 3 ] Dietary lipid is the main structure of biofilms, carriers of fat‐soluble vitamins, and cofactors of hormones and enzymes.…”

“…[ 1–3 ] Dietary lipid is a source of energy and essential fatty acids. [ 3 ] Dietary lipid is the main structure of biofilms, carriers of fat‐soluble vitamins, and cofactors of hormones and enzymes. [ 4,5 ]…”