Reproductive performance of freshwater prawn Macrobrachium rosenbergii (De Man 1879) broodstocks grown on different diets

Abstract

An experiment was carried out during April to September 2013 to compare the reproductive performance of freshwater prawn golda (Macrobrachium rosenbergii) broodstocks fed on diets including 3 commercial (Mega -F₁, SABINCO- F₂ and CP- F₃) and a laboratory formulated test feed (F₄). Post larvae (PL) were collected from the river Kocha of district Pirozpur in April 2012 and nursed in the hapa (net cage) then reared in earthen ponds at the Fisheries Field Laboratory, Bangladesh Agricultural University (BAU), Mymensingh. The broods were fed with selective feeds since their PL stage. The feeding was continued till their maturity of both male and female up to berried females. The proximate composition of the feeds, F₁ where crude protein, 33.49%, lipid 5.38%, carbohydrate 30.31%, F₂-crude protein, 26.70%, lipid 5.50%, carbohydrate 34.34%, F₃- crude protein, 38.90%, lipid 8.09%, carbohydrate 25.37% and treatment F₄- crude protein 33.00%, lipid 11.13%, carbohydrate 25.43%. Feeds were supplied at 5% body weight twice at dawn (5:30-6:00 am) and dusk (5:30-7:30 pm) till the end of the experiment. The variation in most water quality parameters, temperature, alkalinity, DO, transparency, TDS, conductivity NO₂ --N, PO₄ - 3 and chlorophyll-a were insignificant; while parameters, water depth, pH, NH₃-N and NO₃ --N was found to vary significantly (p<0.05) among treatments. Brood observation was carried out by dragging seine net or/and hand picking for eggs in egg chamber remained intact. The male and female ratio estimated 1:2.8, 1: 2.4, 1: 2.4 and 1: 1.7 in the treatments F₁, F₂, F₃ and F₄. The weight of the berried females was 56.33±19.55 g, 85.50±14.85 g, 73.67±23.09 g and 94.50±51.62 g; total weight of eggs was 7.61±1.86g, 7.04±0.69 g, 10.26±1.41g and 6.15±1.20 g in F₁, F₂, F₃ and F₄. The estimated numbers of eggs were 53,889±10,541, 37,555±1,217, 59,640±5,270 and 36,017±7,790 in F₁, F₂, F₃ and F₄ respectively. The weight of berried females with eggs (g), total eggs (g) and estimated number of eggs were significant (p<0.05) among treatments. Females fed with commercial feed F₃ (CP) were found to produce the sufficient number of eggs (59,640/female) followed by F₁ (Mega). The findings may contribute to the better broodstock management of freshwater prawn to produce of a sufficient number of embryonic eggs for hatchery operation.

J. Bangladesh Agril. Univ. 14(2): 229-234, December 2016