Effects of fish-meal, cow blood-meal, and sorghum diets on food utilization and growth of cage cultured Sarotherodon niloticus

The growth responses and feed utilization of Sarotherodon niloticus held in metal cages in a pond and fed diets containing fish-meal, cow blood-meal or sorghum was studied. Results indicate that the best growth, feed conversion and protein efficiency ratio were obtained with the diet containing 60% fish-meal. The growth performance of fish on 40% fish-meal, and 40% and 60% blood meal were not significantly different, and were quite close to the performance with 60% fish-meal. The growth and food utilization of fish on 84% sorghum diet was significantly lower than the rest. The Caged fish without supplemental feeding had a light gain in weight. All fish with supplemental feeding appeared healthy. It is concluded that cow blood meal at 40% or 60% inclusion in diet can adequately replace fish-meal in S. niloticus supplemental diet in pond cultur

Investment prospects of fish farming in the Jos-Plateau, Nigeria

The investment prospects of fish farming in the Jos-Plateau, Nigeria, strategically located in about the centre of the country are discussed with special reference to its numerous abandoned mine lakes and the tripartite role of government, universities and individuals. In the Jos-Plateau, about 17.0 km super(2) is covered by these disused mine lakes, making up about 20-30% of the area covered. In such enterprise, problems commonly encountered, like population growth and government planning policies, fish demand and supply, manpower, feed and seed availability, preservation, processing and marketing are discussed. Inspite of these, prospects still abound with regards to land-use of these numerous disused mine lakes and feed availability based on the principles of using both industrial and farm by-products for fish culture, processing and marketing. These potentials, if properly harnessed, will help to supplement the protein insufficiency in the diet of the populace. In this regard, proposals on the economics of production and sales, strategies for achieving these development goals, cost-benefit analysis and their implications in further development of fish culture are discusse

A preliminary investigation into the effects of a sex-reversal androgen, methyltestosterone, on food utilization and growth of Sarotherodon niloticus (L) fry

Three groups of Sarotherodon niloticus fry were fed for 8 weeks on diets either treated with 17- & methyltestosterone (MT), alcohol (CA), or untreated (CO). Growth rate and food utilization in the different groups were compared. Results indicate that the best growth, Feed Conversion Ratio (FCR), Protein Efficiency Ratio (PER) and Mean Growth Rate (MGR) were obtained with the MT diet. There was no significant difference (P 0.05) in growth and food utilization of the CA and CO fry, nor in the mortality rate of the 3 treatments. The androgen, methyltestosterone promotes growth and protein anabolism without producing toxic effects in S. niloticu

Nutrient digestibility and growth response of rainbow trout (Salmo gairdneri ) fed different carbohydrate types

Seven groups of fingerling rainbow trout (S. gairdneri ) were fed for 10 weeks on 0%, 10%, 20% and 30% of cassava or rice in isonitrogenous diets. Optimum growth and food utilization was at 20% dietary cassava. High fiber content of the control diet did not suppress protein digestibility in this group. Rather, at all levels, protein digestibility was good and remained between 84.4% and 90.1%. However, in the control group, carbohydrate digestibility was very poor. The cassava diets which had the highest digestible energy as carbohydrate produced the best growth performance, food utilization and protein sparing. At the levels studied, the dietary carbohydrates produced no hyperglycamic effect on the fis

Effects of dietary β-carotene on growth and pigmentation of ornamental carp (koi, Cyprinus carpio L.)

The study aimed at testing the effects of dietary β-carotene supplementation on growth, feed utilization and pigmentation of koi carp (Cyprinus carpio) fry (mean weight 0.43±0.00g and total length of 1.34±0.00cm). Five levels of carotenoid concentrations (0.00, 0.003, 0.006, 0.008, 0.010g/kg) were employed to formulate a 38.00% protein balanced diet. The diets were designated and referred to as Control, Diet 1, Diet 2, Diet 3 and Diet 4 respectively. Fish were stocked at 10fish/15.6litre capacity aquaria and reared for 12weeks. Fry were fed in triplicates at 5% body weight. The database was analyzed and results revealed a dose dependent percentage weight gain with koi carp treated with the extracts experiencing 667.44±10.48%, 691.47±2.79%, 865.12±16.33% and 854.34±12.42% for Diets 1 to 4 respectively. Proximate analysis of fish flesh revealed no significant differences (p<0.05) between treatments in all the parameters. Astaxanthin dominated the body of koi carp, regardless of the concentrations of dietary β-carotene included in the diets. Survival rates were generally high and was not particularly dependent on carotenoid inclusion level. Inference from the study showed that β-carotene at 0.003g/kg to 0.010g/kg inclusion in the diets resulted in increased food conversion, mean weight gain, specific growth rate and protein efficiency ratio. Keywords: β-carotene, growth, survival, feed utilization, koi carp

Occurrence, Abundance, Food and Feeding Habits of Fish Species in Cross River Estuary (Ibaka Beach), Nigeria

Occurrence, abundance, food and feeding habits of fish species in Cross River Estuary was studied for five months. A total of 386 fish samples comprising of 23 families, 29 genera and 40 species were collected. The most abundant species were Arius gigas, Ethmalosa fimbriata, Ilisha africana, Cynoglossus senegalensis, Liza falcipinnis, Galeoides decadactylus, Pseudotolithus senegalensis and Trichiuris lepturus, which occurred throughout the sampling period. The least abundant species were Carcharhinus falciformis, Mugil cephalus, Lutjanus goreensis and Sphyraena sphyraena. The most abundant family was Sciaenidae (15.30%), followed by Clupeidae and Ariidae (14.80% and 11.16% respectively). Out of the 386 specimens examined, 77(19.95%) had empty stomach, 65(16.83%) had full stomach while 80(20.73%), 89(23.06%), and 75(19.43%) had ¾, ½ and ¼ respectively. Animal preys dominated the stomach contents of the dominant predatory groups. Other items found in the stomachs of some species were partially digested plant parts and mud. Stomach content analysis revealed that fishes of Cross River estuary were mostly euryphagous with few detritus and filter feeders. Diversity indices revealed significant differences among species and the mean condition factor was 2.27. Keywords: Fish Species, Occurrence, Food, Feeding Habits, Cross River Estuar