Effects of feed restriction and refeeding on compensatory growth of Labeo rohita in fertilized ponds

The present study evaluated the effect of cyclic feed restriction and re-feeding protocols on compensatory growth, nutrient utilization, digestive enzyme activity, and physiological responses of rohu ( Labeo rohita ) cultured in fertilized ponds. The experiment was conducted in twelve earthen ponds (0.04 ha each) prepared according to standard pre-stocking management practices recommended by ICAR-Central Institute of Freshwater Aquaculture, Bhubaneswar. Rohu fingerlings were stocked at a density of 7500 fish ha⁻¹ with three replicates per treatment. The study was carried out for 10 month under fertilized pond conditions, and fish were fed formulated feed at 1.5–3.0% of their body weight, depending on size. Four feeding regimes were evaluated: continuous feeding (Control) and three cyclic feed restriction and re-feeding schedules, viz., T-1 (2 month feeding → 1 month restriction → 1 month refeeding → 1 month restriction → 5 month refeeding), T-2 (2 month feeding → 2 month restriction → 1 month refeeding → 1 month restriction → 4 month refeeding), and T-3 (2 month feeding→ 3 month restriction → 1 month refeeding → 1 month restriction → 3 month refeeding). The results indicated that cyclic feeding regimes significantly affected growth performance and nutrient utilization. The T-1 group exhibited slight overcompensation (104.24%) with final weight (662.61 ± 4.69 g) and production (5494 kg ha⁻¹) comparable to the control, while partial compensation was observed in T-2 (81.88%) and T-3 (76.28%). Apparent feed conversion ratio (AFCR) and protein efficiency ratio (PER) did not differ significantly ( p = 0.085) among treatments. However, the highest specific growth rate (SGR) was recorded in T-1. Protein productive value (PPV) and lipid productive value (LPV) were significantly higher ( p = 0.008) in restricted feeding groups than in the control. Digestive enzyme analysis revealed significantly higher protease and lipase activities in the control and T-1 groups compared with T-2 and T-3. Haemoglobin levels did not differ significantly among treatments, although a decreasing trend was observed with increasing feed restriction. Blood glucose levels were significantly lower ( p < 0.001) in the control and T-1 groups than in T-2 and T-3. Overall, the T-1 feeding protocol achieved full growth compensation without compromising growth or feed efficiency.