Effect of alternate day feeding strategy of sub-optimal protein level on haemato-biochemical responses in Labeo rohita (Hamilton) juveniles.

A feeding trial was conducted for 60 days to delineate the effect of alternate day feeding strategy of sub-optimal protein level on haematological parameters, serum parameters and phagocyte respiratory burst activity (NBT) in Labeo rohita juveniles. One hundred and thirty-five fingerlings (1.87 ± 0.01-2.26 ± 0.05 g) were distributed in triplicate groups of each treatment, and fish were fed at 5% body weight daily. Three experimental isocaloric (401.32-410.28 kcal/100 g) diets of 30%, 25%, and 20% crude protein designated as diet A, diet B, and diet C respectively, were prepared, using locally available feed ingredients. Three different feeding schedules of normal protein diet continuously (diet A-30%), alternate feeding of 1-day diet A followed by 1-day diet B (1A/1B) and alternate feeding of 1-day diet A followed by 1-day diet C (1A/1C) were tested. The total erythrocyte count and haemoglobin content was significantly (p < 0.05) enhanced in the group T1 fed (1A/1B), and the lowest count was recorded in the group T2 fed (1A/1C). Total leucocyte counts, total serum protein, and serum globulin were higher in the group T1 fed (1A/1B) and lower in the group T2 fed (1A/1C) as compare to control. The respiratory burst activity (NBT) of blood phagocytes and serum A-to-G ratio was recorded significantly difference in among the treatment groups. Based on the results of the present study, it is concluded that alternate feeding of 1-day diet A followed by 1-day diet B (1A/1B) is equally effective and promote the immunity in Labeo rohita juveniles.

Higher water temperature enhances dietary carbohydrate utilization and growth performance in Labeo rohita (Hamilton) fingerlings.

A 60-day experiment was conducted to delineate the effect of three dietary levels of gelatinized carbohydrate (GC) on growth, nutrient-utilization and body composition of Labeo rohita fingerlings (avg. wt 6.5 ± 0.3 g) reared at two water temperatures (ambient-AT (26 ± 0.8 °C) and 32 °C). Two hundred and sixteen fingerlings were randomly distributed into six treatments in triplicates. Three semi-purified isonitrogenous diets were prepared with graded levels of GC viz. D(1) : 40%, D(2) : 50% and D(3) : 58%. Growth rate, feed efficiency and protein efficiency ratio were significantly (p < 0.05) higher in 50% GC and 32 °C reared groups than their AT counterparts. Hepato Somatic Index was higher in AT reared groups compared to 32 °C reared counterparts. Apparent digestibility co-efficient of carbohydrate was significantly (p < 0.05) higher at 32 °C reared groups but decreased with increasing carbohydrate (GC) levels. Fish reared at 32 °C showed significantly (p < 0.05) higher amylase, protease and hexokinase activities while glucose-6-phosphate dehydrogenase and glucose-6-phosphatse were significantly (p < 0.05) higher at ambient temperatures. The results obtained in present study indicated that L. rohita could utilize higher level (50%) of dietary carbohydrate at 32 °C.