Effect of animal and plant protein diets on growth and reproductive performance in an ornamental fish, Xiphophorus helleri

Abstract

Pellet feeds were prepared with different levels of protein (10, 15, 25, 35 and 45%) from animal and plant sources and tested on growth and reproductive performance (fertility) for a period of 210 days in the red swordtail Xiphophorus helleri. Fish fed with 45% animal protein (AP) and plant protein (PP) showed the maximum mean body length and weight, conversion rate (growth rate), gonad weight and fertility than any other protein levels tested. Animal protein induced gonad development earlier than PP diets. Female X. helleri fed on 45% AP
had 14 times more gonad weight (79 mg wet weight) than those fed with same level of PP diet (5.5 mg wet weight) on day 84. Animals fed with PP bred 1 to 3 times depending upon the level of protein, whereas all groups fed with AP bred 3 times except the lowest protein (10%) level. Fertility trials showed that 45% AP or PP diets yielded the highest fry production and short interbrood interval as compared to other protein
diets and hence 45% AP or PP is considered as optimum level for X. helleri. The necessity for incorporating optimum level of AP source in the diet for maximum reproductive performance in X. helleri is discussed.