An 8-week feeding trial was conducted to determine the optimum dietary protein and lipid levels for growth, feed utilization and body composition of goldfish, Carassius auratus juveniles (1.66 ± 0.018 g). Six diets containing two protein levels (300 and 400 g/kg) and three lipid levels (40, 80 and 120 g/kg) were formulated. Fifteen fish were randomly allotted to 18 aquaria (0.6 × 0.3 × 0.45 m) and fed to apparent satiation. The results showed that weight gain and specific growth rate (SGR) increased in response to higher dietary proteins with highest weight gain and SGR recorded in diet containing 400 g/kg protein with 80 g/kg lipid. Both feed intake (FI) and protein efficiency ratio (PER) were dependent on dietary protein and lipid level (P less than 0.05). Lipid retention (LR) was negatively correlated while hepatosomatic index (HSI) and viscerosomatic index (VSI) was positively correlated with dietary lipid levels. Whole body protein content decreased (P less than 0.05) while, lipid content increased with increasing dietary lipid at each protein level. Second-order polynomial regression also revealed diet containing 400 g/kg protein level and 80 g/kg lipid level optimal for the growth and feed utilization of juvenile goldfish, C. auratus.

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The mince of rohu (Labeo rohita) fish was used to develop susages using microbial transglutaminase (MTGase). The functional (gel strength, water holding capacity, folding score), textural, colour characterstics, protein pattern and microstructure of the mince sausages prepared using MTGase (0, 1, 1.5 & 2%) were studied. MTGase positively enhaced the gel strength, water holding capacity, and folding score of the prepared sausages with an increment in concentration of MTGase. MTGase effectively cross-linked proteins in the gel network as revealed in protein patterns, despite presence of sarcoplasmic proteins. Although low, but the gel strength of mince sausages was found to be comparable with surimi and surimi-based gel products. The different concentration of MTGase did not show any significant influence (p > 0.05) on the textural properties of susages such as hardness, cohesiveness, adhesiveness and elasticity. The variation in colour characteristics of cooked mince sausages particularly whiteness arises from the pigments in mince and the colour of MTGase used during formulation of sausages. MTGase added sausage samples had a finer and homogenous protein network with a smaller void when compared with the gel of mince without MTGase in microstructure analysis. Though potential additive for improvement of functional properties of sausages, availability and cost of MTGase limits its use in the development of value-added fish products such as sausages from mince of freshwater fish.

To establish an effective feeding regime for Carassius auratus, this experiment investigated the effects of feeding ration and feeding frequency on growth, feed utilization and body composition in juvenile C. auratus (Initial weight: 1.66 ± 0.018 g). A 4 × 4 experimental design of four ration sizes (2, 3, 4 and 5% body weight per day [BW/day]) with four feeding frequencies (1, 2, 3 and 4 meals/day) was carried out over 8 weeks with three replicates per treatment. The results showed that weight gain and specific growth rate (SGR) increased significantly (P less than 0.05) with the feeding ration from 2% BW/day to 3% BW/day and feeding frequency from 1 meal/day to 4 meals/day. Similarly feed conversion ratio (FCR) and protein efficiency ratio (PER) were significantly better (P less than 0.05) at feeding ration of 3% BW/day than 4 and 5% BW/day at 4 meals/day than 1, 2 or 3 meals/day. SGR, FCR and PER further reduced when feeding ration was increased beyond 3% BW/day. Lipid content improved with the increased feeding frequency at all feeding rations, however feeding frequency did not exhibit a significant effect on crude protein level (P>0.05). Moisture content of body showed an opposite trend to lipid content and decreased with increase in feeding frequency. In conclusion, feeding ration of 3% BW/day and feeding frequency of 4 meals/ day was found to be better for maximal growth and feed utilization of young ones of C. auratus.