Pulsed Feeding Regimes for the Rearing of Labeo rohita (Hamilton) Fry: A Climate Smart Approach

Climate-Smart Aquaculture (CSAq) is built on three pillars, i.e., sustainably increasing productivity and income, improving resilience and mitigating climate change, respectively. Feed constitutes 60%-80% of the total production cost in aquaculture. The reduction of feed cost as well as the pollution originating from uneaten feed have always attracted the attention of aquaculture researchers. Adoption of an optimal feeding regime reduces both feed cost and nutrient loading in the ponds and in turn, enhances the income of farmers and reduces environmental impacts of aquaculture practices. Mixed feeding schedules, pulsed feeding or intermittent feeding have been proposed as some of the climate-smart methods to reduce feed cost and pollution by aquaculture and it has been successfully tested in many fish species. There is lack of sufficient reports on the impact of feeding regimes on the rearing of Labeo rohita, Rohu fry. The information will be useful to farmers for rearing of fry to fingerlings with reduced cost and environmental impact.

A 90-day experiment was conducted to evaluate the growth performance and feed utilization of Labeo rohita fry under pulsed feeding regimes as a climate smart approach. For the experiment, the feeding regimes followed were, control (daily feeding @5% of the biomass), 1D4R (1 day starvation+ 4 days refeeding at 5% of the biomass), 2D12R (2 days starvation+ 12 days refeeding at 5% Biomass), 4D16R (4 days starvation+ 16 days refeeding at 5% biomass). The data obtained were subjected to statistical analysis using SAS 9.3. PROC GLM was used for analysis of variance (ANOVA) and Tukey’s Honestly Significant Difference (HSD) test was used for all possible pair comparison of treatments at 5% level of significance.

The fishes under 1D4R exhibited significantly higher weight gain, SGR and feed conversion efficiency (FCE) and significantly lower FCR and production cost than the control group. Water quality parameters like Total NO₂, NO₃, total ammoniacal nitrogen and total phosphate were higher in the control group than in the treatments. The results suggest that one-day feed restriction followed by four days of refeeding could be an efficient strategy for rearing Labeo rohita fry to reduce production costs and environmental impact without compromising growth.