Evaluation of polanga (Calophyllum inophyllum) oil cake as a non-conventional ingredient in Labeo rohita (Hamilton, 1822) fingerling feed

Abstract

In the present study, polanga (Calophyllum inophyllum) oil cake (POC) was evaluated as a non-conventional ingredient in Labeo rohita (Hamilton, 1822) fingerling feed. Proximate composition and fatty acid analysis of POC indicated that it can be a good source of protein (24.2%) and energy (4.4 kcal g-1). Fatty acid analysis indicated that it is dominated by monoenes (39%) followed by saturates (28.42) and polyunsaturated fatty acids (PUFA) n-6 (27.76%). Further, phenol, tannin and flavonoids were detected as prominent secondary metabolites. Five iso-nitrogenous (25-26%, crude protein) feeds incorporated with POC @ 0% (F1), 10% (F2), 20% (F3), 30% (F4) and 40% (F5) level were fed to L. rohita fingerlings for 90 days in indoor conditions. At the end of the experiment, it was observed that survival percentage (95-97%) of F1, F2 and F3 groups was statistically similar which was significantly higher (p<0.05) compared to F4 and F5. The gain in weight and specific growth rate (SGR) of F1 and F2 were similar but next higher inclusion levels of POC significantly (p<0.05) reduced the growth in F3, F4 and F5 groups. In addition, feed conversion ratio (FCR) was significantly lower (p<0.05) and similar in F1and F2. Protein efficiency ratio (PER) and net protein utilisation (NPU) were found significantly higher (p<0.05) in F1 and F2 as compared to the rest of the groups. Haemoglobin, serum protein, albumin and globulin in blood were similar in F1 and F2 (p>0.05), which were significantly higher than the levels in other groups (p<0.05). Serum glutamic-oxaloacetic transaminase (SGOT) and glucose levels increased significantly in F3, F4 and F5 groups compared to F1 and F2. POC was used for the first time in carp feeds as a non-conventional feed ingredient during this study and the results clearly indicated that POC could be incorporated @ 100 g kg-1 in the feed of L. rohita fingerlings without any adverse effect on growth, survival and nutrient utilisation.