Effect of salinity on food consumption and growth of juvenile Nile tilapia (Oreochromi niloticus L.)

The effect of salinity (0, lO and 20%o, water temperature 28 ± l oC) on food consumption and growth of juvenile Nile tilapia, Oreochromis niloticus L. (9.94 ± 0.15 g) were investigated by feeding group of 20 fish at 2% body weight day. Individual food consumption was measured using X-radiography. There were no significant differences in growth or white muscle protein concentrations among groups. During feed deprivation, weight loss was similar for fish held at O%o and 10 %o salinity, but after 7 days over 50% of the fish maintained at 20%o salinity developed lesions covering 5-25% of the body. No significant relationships were observed between individual specific growth rates and food consumption rates within the groups. The fish in all salinity groups showed a negative correlation between specific growth rate and food conversion ratio. The coefficient of variation for wet weight specific food consumption and the mean share of meal for each fish were used as a measure of social hierarchy strength. A negative correlation was observed between coefficient of variation in food consumption and mean share of meal. The social hierarchy structure was similar in all salinities; 25% of the fish were dominant (18.29% above an equal share of meal) and 30% were subordinate (16.19% below an equal share of meal) and the remainder 45% fish fed theoretical share of meal (MSM, 5.26%).

Growth and survival of Penaeus monodon postlarvae fed shrimp head meal and fish meal as primary animal source of protein

Although shrimp head meal alone does not provide for good growth and survival, fish meal can provide high survival rate. The addition of shrimp head improves this diet. It is suggested that cholesterol present in shrimp could have caused this difference. Composition of the test diets is tabulated, as are proximate chemical analysis of the diets, and the mean initial weights, final weights, weight gains, survival rate, feed consumed, protein consumed, of Penaeus monodon postlarvae, feed conversion and protein efficiency ratio.

A preliminary study on the evaluation of casein, shrimp meal, squid meal and spirulina as protein sources of Penaeus monodon (Fabricius) postlarvae

P. monodon postlarvae were fed with fresh brown mussel (Modiolus metcalfei ) meat, and artificial diets containing casein, shrimp (Metapenaeus ensis ) meal, squid (Loligo ) meal, and Spirulina as protein sources at a rate of 20% of their biomass per day for a period of 10 days. No statistical difference was found among the weight gains of shrimp fed on various experimental diets. However, shrimp fed squid meal diet had highest weight gain followed by shrimp meal, fresh brown mussel meat, casein and Spirulina . Shrimp fed squid meal diet had a significantly better feed conversion and those receiving other experimental diets. Poorest fed conversion was observed in shrimp fed Spirulina . The protein efficiency ratio was statistically highest for the squid meal diet, with the lowest value again for Spirulina diets. Survival rate was significantly highest for shrimp fed the shrimp meal diet. No statistical differences were found among shrimp fed other experimental diets. Appropriate data are tabulated.

Suitable stocking density of tilapia in an aquaponic system

An aquaponic system was studied through the integrated culture of mono-sex GIFT and two types of vegetables viz. morning glory, Ipomoea reptans and taro, Colocasia esculenta in a recirculating system for 15 weeks. Tilapia fry of uniform size of 0.76 g were released in three treatments (stocking densities): 106 fish/m³ (T1), 142 fish/m³ (T2) and 177 fish/m³ (T3) to assess the effect of stocking density on the growth performance of fish. Fish were fed with a commercial feed containing 25% protein. Weight gain (g) of tilapia ranged from 19.41 to 32.67 g and was inversely related with stocking density. Percent weight gain varied between 2553.99 and 4298.68% and was significantly different among the treatments. SGR ranged from 3.09 to 3.59% per day and varied significantly. FCR varied from 2.19 to 2.69 and had a positive correlation with stocking density. The highest survival rate (%) was achieved in T1 (99%) followed by T2 (98%) and T3 (96%). Production of fish ranged from 3.43 to 3.52 kg/m³ and was inversely related with stocking density. The present study demonstrated that 106 fish/m³ was the best stocking density in terms of growth, food conversion ratio, survival and production for tilapia culture in the aquaponic system.

Preliminary investigation on growth responses of Cyprinus carpio L. fed on locally formulated artificial diets

The growth rate and feed conversion ratios of the common carp, Cyprinus carpio were measured for five test diets in 14-day replicate laboratory studies. The young carp were fed with artificial test diets with crude protein contents ranging from 14.50 to 21.42 per cent. Within this range of feed characteristic optimum growth rates were obtained with diets containing 20.25 and 21.42 per cent crude protein. The study of the effect of varying ration levels showed that growth rates increased with increases of ration size, but the food conversion efficiency and protein efficiency ratios decreased markedly as ration size was increased

The effects of supplemental feeds containing different protein: Energy ratios on the growth and survival of Tilapia nilotica (Oreochromis niloticus) in brackishwater ponds

A research was conducted in thirty approximately 100 sq.m earthern ponds of the Brackishwater Aquaculture Centre (BAC), College of Fisheries, University of the Philippines, Leganes Iloilo from November 7, 1982 to March 7, 1983 to evaluate the effects of nine supplemental feeds containing different protein: energy ratios on the growth and survival of Tilapia nilotica in brackishwater ponds. Nine supplemental feeds formulated were with protein levels of 20%, 25%, and 30% each at three energy levels of 3,000 kcals; 3,500 kcals; and 4,000 kcals. There was a control treatment with no feeding so that mean weight gain growth rate, feed conversion rate, and survival were determined. Fish fingerlings were acclimated from 0-29 ppt. salinity before the experiment and 20% of fish in each treatment were sampled after every 30 days. Growth rates were significantly different and increased with increasing energy level at the 30% protein feeds but decreased at high energy levels in the 20% and 25% protein feeds. Feed conversion was significantly different due to interaction between protein and energy levels in the feeds, and was better at the 30:3,500 kcals feeds having a feed conversion of 1.55 g. Survival was not significantly different

Comparison of extruded and non-extruded soy meals in the diet of genetically improved mudfish Heterobranchus longifilis juveniles

Raw soybeans were subjected to three different processing methods viz Parboiling, Toasting and Extrusion with an Intra Pro Extruder. The processed soybean meals were thereafter incorporated at equal levels into the diets of genetically improved mudfish Heterobranchus longifilis juveniles. The fish were fed the experimental diets in triplicate at 5% of their body weight for eight weeks. The growth performance and food utilization indices, namely Mean Weight Gain (MWG), Food Conversion Ratio (FCR), Specific Growth Rate (SGR%) and Protein Efficient Ratio (PER), were monitored bi-weekly. The results show that fish fed the control fishmeal diets were highest in growth performance, which was significantly different (P>0.05) from others. Among the fish fed the test diets, those fed toasted soybean had higher MWG, SGR, FCR and PER than juveniles fed the parboiled soybean diet. The juveniles fed the extruded soybean diet recorded the least growth performance. The implication of these results in diet formulation is discussed

Growth performance of exotic Oreochromis niloticus, exotic Oreochromis niloticus fed with pelleted feeds in flow-through system

Local, exotic and hybrid tilapia fingerlings were fed 45% crude protein diet containing 18% fish meal in a flow through system in triplicate and their growth and food utilization observed for 14 weeks. At the end of the study, the hybrid (Exotic Oreochromis niloticus male x Exotic Oreochromis aureus female) fingerlings had higher growth rate and food conversion ratio (FCR) than the other treatments. This was followed by Exotic Oreochromis niloticus fingerlings. The exotic Oreochromis niloticus fingerlings came next while the local Oreochromis niloticus fingerlings were the least in growth performance. The survival rate of the local O. niloticus was however higher than the other treatments

Growth performance of Clarias gariepinus fingerlings fed earthworm meal (Lumbricus terrestis)

An investigative study was carried out on the growth performance and nutrient utilization of (Clarias gariepinus) fingerlings fed earthworm meal as a replacement for fish meal. A large collection of earthworm was done during the peak of rainy season (July-August) within the University environment. They were then ovens dried. Used as test ingredients were 0% (Diet 1) 50% (Diet 2) and 1000% (Diet u). The trials were conducted in plastic bowls (40-L capacity) under laboratory conditions. The diets were fed at 5% body weight to fish; the fish were stocked at 10 fish per bowl. The evaluation of the growth parameters showed that there was no significant difference (P>0.05) in mean weight gain (MWG) specific growth rate (SGR) food conversion ratio (FCR), protein efficiency ration (PER) and survival among the fish fed the experimental diets

Effect of darting phenomenon of African catfish Heterobranchus longifilis (Burchell 1822) on growth performance of Nile tilapia: Oreochromis niloticus (Linnaeus, 1758)

Replicate Ponds of 0.02ha stocked at 500 catfishes with 20,000 tilapia/ha were used to assess growth performance of O.niloticus, average weight 50.4g with (i) darted catfish; H.longifilis (shooters) average weight 60.3g (ii) non-shooters of H.longifilis, average weight 35.4g. Final mean weight, mean growth rate, specific growth rate and food conversion ratio were 499.5g 26g/day, 1.36% and 5.58% respectively for O.niloticus stocked with longifilis (shooters and 440.4g 2.3g/day 1.23% and 5.58% respectively for O.niloticus stocked withH.longifilis (non- shooters) and 246.9g, 1.2g/day, 0.93, 6.30% respectively for tilapia in monoculture. The least growth was noted for O. niloticus in monoculture while the best growth was recorded O. niloticus in polyculture with darted catfish

Effects of fermented fluted pumpkin leaf (Telfaria occidentalis) on the growth and nutrient utilization of Clarias (Clarias gariepinus)

Clarias (Clarias gariepinus) (Burshell, 1821) fingerlings were fed isonitrogenous diets (38.9% crude protein) with fermented fluted pumpkin leaves (FFPL) replacing different proportion (0,50,75,100%) of extruded soybean meal (ESM) for 8 weeks. Growth responses at the different substitution levels measured. Increasing FFPL intake resulted in better weight gains and higher specific growth rates (SGR) of 0.29, 0.36 and 0.38% per day respectively. The increase in growth from feeding diets containing 75% and 100% of the ESM replaced with FFPL were significantly higher (P<0.05) than those of other diets. Further more fish tissue protein deposition consistently increased with increasing level of FFPL concentration in their diets. Fish fed diets where whole ESM was replace 100% FFPL gave the best overall response in terms of their weight gain, food conversion ratio, protein efficiency ratio, and specific growth rate. Economic considerations indicate the replacement of ESM with FFPL, which is a cheaper ingredient in feeds for Clarias

Growth response of Heterobranchus longifilis fingerlings fed with varying levels of dietary freshwater mussel (Aspatharia sinuata)

A common bivalve: Freshwater mussel, Aspatharia sinuate was evaluated as a dietary protein supplement in the production diet for Heterobranchus longifilis fingerlings with mean body weight 8.34 plus or minus 10g reared in aquaria tanks. Four diets containing fishmeal protein at a rate of 25%, 50% and 75% along with the freshwater mussel flesh were formulated. The diet without the freshwater mussel served as the control. The fish fingerlings were fed at 5% body weight per day for 56 days. It was revealed at the end of the experiment that freshwater mussel was most suitable as a protein supplement when incorporated at 25% replacement. The body weight gain, specific growth rate and feed conversion ration values of 6.83g, 1.06% day and 0.62 respectively were highest in diet with 25% replacement closely followed by diet with 50% replacement. Beyond 75% inclusion level there was no significant growth (P>0.05). However, complete replacement of fishmeal by freshwater mussel decreases growth rates and should not be used in Heterobranchus longifilis diets

Effect of darting phenomenon of African catfish Heterobranchus longifilis (Burchell 1822) on growth performance of Nile tilapia: Oreochromis niloticus (Linnaeus, 1758)

Replicate Ponds of 0.02ha stocked at 500 catfishes with 20,000 tilapia/ha were used to assess growth performance of O.niloticus, average weight 50.4g with (i) darted catfish; H.longifilis (shooters) average weight 60.3g (ii) non-shooters of H.longifilis, average weight 35.4g. Final mean weight, mean growth rate, specific growth rate and food conversion ratio were 499.5g 26g/day, 1.36% and 5.58% respectively for O.niloticus stocked with longifilis (shooters) and 440.4g 2.3g/day 1.23% and 5.58% respectively for O.niloticus stocked with H.longifilis (non- shooters) and 246.9g, 1.2g/day, 0.93, 6.30% respectively for tilapia in monoculture. The least growth was noted for O. niloticus in monoculture while the best growth was recorded O. niloticus in polyculture with darted catfish

Essais d'utilisation de "nourrisseur à la demande" pour l'alimentation de Chrysichthys nigrodigitatus en cage-enclos

An experiment using demand feeder was carried out on the catfish Chrysichthys nigrodigitatus reared in cage-enclosure in the lagoon Ebrié (Côte d'Ivoire). The study lasted 5 months, from October to March, and showed that the demand feeder improves the growth rate of the fish and the feed conversion. It was able, as well as the conventional hand feeding, to show monthly variations of performances.

The evolution of body muscle composition of the African catfish (Clarias gariepinus) (Burchell 1822)

Changes in body muscle composition of Clarias gariepinus were studied in fish reared from 1.08 g to 383 g mean body weight in a 201-day culture period. Changes in the amount of protein content, dry matter and ash free dry matter in the muscle tissue can be described as a function of body weight. The percentage of protein content was observed to be higher in bigger fish. Fat content was low throughout the fingerling stage. Specific growth rate decreased significantly at 400 g mean body weight (P<0.05) while feed conversion rate increased. The conclusion, based on the culture conditions in this study, is that the optimal weight for harvesting C. gariepinus is 400 g.