Nutritional interventions to enhance reproductive performance and larval rearing of dwarf gourami Trichogaster lalius (Hamilton, 1822)

Considering the importance of broodstock nutrition, the reproductive performance and larval rearing of dwarf gourami Trichogaster lalius (Hamilton, 1822), were evaluated in response to nutritional interventions under captive conditions for 90 days. To evaluate reproductive performance, four dietary treatments were tested. Treatment 1 and 2 received formulated feed supplemented with 0 and 4% supplementary diet mix (SDM). SDM comprised, Refined lecithin, α Tocopheral acetate, L-ascorbic acid, Spirulina powder and L-tryptophan. Treatment 3 was fed with live feed (Tubifex), while Treatment 4 received a combination diet, comprising live feed (Tubifex) and 4% SDM-formulated feed. Among both male and female dwarf gourami, the highest gonad weight and gonadosomatic index (GSI) were observed in Treatment 4. Spawning was successful only in Treatment 3 and 4. After 60 days, fertilisation rates in Treatment 3 and 4 were 65.33±1.76 and 70.67±0.67% respectively, while hatching rates were 35.33±1.76 and 42.00±1.15% respectively. The combination diet in Treatment 4 yielded better results in terms of fertilisation and hatching success. For larval rearing, a 30-days experimental trial was conducted in triplicates, with a stocking density of 100 larvae per 10 l water. Three dietary treatments were used: Treatment 1 fed with live feed (Infusoria), Treatment 2 fed with 4% SDM-formulated feed and Treatment 3 fed with boiled egg yolk. The highest larval length gain (10.54±0.07 mm) and survival rate (66.33±0.88%) were recorded in Treatment 1, fed with live infusoria. Keywords: Breeding, Larval rearing, Nutritional intervention, Spawning success, Trichogaster lalius