Studies on the quality, factors affecting motility and short - term storage of milt of the Indian mackerel, Rastrelliger kanagurta

A detailed study was conducted on the monthly variation in milt-volume, spermatozoa concentration and duration of motiUty of spermatozoa oi Rastrelliger kanagurta. Milt-volume showed peak (0.094 ml) in the month of May. Spermatozoa concentration did not vary much during the period of May to October (21.5-21.7 x lO'ml"'). Duration of motility in 100% seawater was observed to be maximum in the month of August (101.6 sec.) followed by October (96.53 sec.) and April (94.4 sec). The effect of various dilutions of seawater on the duration of motility showed a decreasing trend with decrease in concentration. Maximum duration of motility (86.46 sec.) was observed in 100% seawater

Rotifer as live feed for larviculture of marine fishes - a research review

The most critical factor in the commercial farming offish and shellfish is the dependable availability of healthy fry produced in hatcheries. Most of the fishes having aquaculture potential have larvae with very limited yolk reserves and the transition stage from endogenous to exogenous feeding is very critical, often resulting in mass mortalities. The recent success in the consistent supply of many marine and brackish water fish seeds can be attributed to the mass production technologies of high quality live feeds

Livol (IHF-1000), a new herbal growth promoter in white prawn, <i style="">Penaeus indicus</i> (Crustacea)

38-43Livol (IHF-1000), new herbal product has been found as a potent growth promoter to stimulate the growth of white prawn. Juveniles of P. indicus were fed with livol at four dosages viz; 1.0%, 1.5%, 2.0% and 2.5% through a fish meal based supplementary diet having 40% protein. All levels of Livol administration produced significantly (P < 0.01) higher growth than control but the diet containing 1% livol promoted maximum growth, high conversion efficiency and improved nutrient digestibility. Specific growth rate (SGR%) was also maximum in 1% livol. Digestive enzymes activity (amylase, protease and lipase) was higher in the midgut of prawns fed livol diets. RNA/DNA ratio in the muscle and hepatopancreas of prawn fed livol were higher than control. The total dry matter contents of the carcass increased in the livol treated prawn while lipid, carbohydrate, fiber and ash contents showed no significant variation. The study indicated that livol could be recommended as a safe growth promoter for enhancing shrimp growth and production

Effect of hormones on growth, food conversion and proximate composition of the white prawn, Penaeus indicus (Milne Edwards)

232-235Juveniles of P. indicus were fed testosteron propionate (TP), diethylstilbestrol (DES) and human chorionic gonadotropin (HCG) and their three levels of combinations. incorporated in tile diet for 90 days. Prawns fed hormone diet showed significant difference in growth (P < 0.01) to that of control except in the case of HCG (20 ppm) which inhibited growth. The diet containing a combination of HCG (10 ppm) and TP (1.5 ppm) showed superior growth, better feed consumption, feed conversion efficiency. assimilation and protein and lipid digestibility. Crude protein and lipid contents were also higher in the prawns feel this diet compared to control

Dietary administration of testosterone propionate on growth, proximate composition and residual content of pearlspot, <i>Etroplus suratensis</i> (Bloch) (Cichledae)

173-179Juveniles of pearlspot were fed a synthetic hormone testosterone propionate (TP) at levels 1, 2, 3, 4 and 5 ppm incorporated in a prepared supplementary diet having 40% protein for 120 days. Fishes fed diet containing 4 ppm testosterone propionate showed significantly (p<0.01) superior growth than control and other levels of TP. Improvement in feed utilisation in terms of better feed consumption, higher feed conversion efficiency, enhanced nutrient digestibility and increased digestive enzymes activity was observed in the fishes fed 4 ppm TP. High RNA, DNA contents and RNA/DNA ratio in the muscle and liver were noticed in the TP treated fishes. The muscle protein content of TP fed fishes was significantly (p<0.01) increased from that of the control. Residual hormone content found in the treated fishes on termination of the experiment (120 days) has been dropped to the normal level as that of the control on the 30th day after stop feeding hormone diet. Testosterone propionate at 4 ppm level can be suggested as the optimum dosage required to bring about an additional growth increment. (111.02%) without any residual hormonal effect

Growth characteristics of white prawn <i>Penaeus indicus</i> (Decapoda-Crustacea) under dietary administration of protein hormones

389-395The role of protein hormones on the growth characteristics of Penaeus indicus was evaluated with a view to improve the growth potential and production of the shrimp in aquaculture. The hormones, human chorionic gonadotropin (HCG) and L-thyroxine (T4) were incorporated into a prepared supplementary diet. HCG was administered at dosages of 2.5, 5.0, 7.5, 10.0, 12.5 and 15.0 ppm while thyroxine was incorporated at the levels of 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, and 0.07 ppm. Growth, feed utilization, digestive enzymes activity, nucleic acid contents and proximate composition were monitored. All levels of the protein hormones were found to enhance growth. A diet containing 12.5 ppm of HCG or 0.04 ppm of thyroxine brought about the highest growth (12.68 g, 13.3 g respectively). Viscerosomatic index decreased while gonadosomatic index increased due to HCG treatment. Feed conversion efficiency, assimilation efficiency and apparent protein and lipid digestibility showed increase in the hormone supplemented shrimps. In the muscle and hepatopancreas of shrimps under hormone treatments, RNA/DNA ratio were higher than that of the control. The total dry matter and protein contents of the body increased (P<.01) while no significant change was noticed in the lipid content of the hormone treated shrimps. Protein hormones appear to promote growth by stimulating the feed conversion efficiency and nutrient digestibility through enhanced digestive enzymes activity and accelerated protein synthesis in P. indicus (M. Edwards)

Effect of dietary hormones on food utilization, growth and bodycomposition of the pearlspot, <i>Etroplus suratensis</i> (Bloch) in a brackish water pond

32-36The influence of hormones (testosterone propionate, diethylstilbestrol, human chorionic gonadotropin) and their combinations on the growth of pearlspot fingerlings was assessed for 90 days by feeding the hormones through fish meal based pelleted diet containing 40% protein. The hormone treated fishes showed significant increase in growth (P < 0.001) than the control. Human chorionic gonadotropin promoted better growth, feed conversion efficiency and maximum protein digestibility. The combinations of all the three hormones in the diet performed better than the two hormone combinations. From the present study. it can be concluded that the hormones stimulated growth of pearlspot, through the combined influence of enhanced food intake, high food conversion efficiency, better digestion, assimilation and increased protein synthesis