Effects of Dietary Soybean (Glycine max) on Growth Performance, Haematology and Serum Biochemistry of African Carp (Labeo Cubie Ruppell 1832)

The effects of dietary replacements of fish meal with soybean meal on growth performance, heamatology and serum biochemistry in juvenile Labeo cubie were evaluated. Four hundred and fifty (450) apparently healthy juvenile Laboe cubie were distributed into one of fifteen 1000 L tanks divided into five groups and fed any of diets A (0% soybean meal); B (30% soybean meal); C (40% soybean meal); D (45% soybean meal) and diet E (75% soybean meal) for 56 days. At set time points day 7, 14, 28 and day 56, five fish were randomly selected per tank for growth assessments, heamatology and serum biochemical evaluations. Growth performance indices decreased significantly (p < 0.05) along the gradient of soybean meal inclusion and the duration of feeding. The erythrocytes count increased significantly (p < 0.05) at day 14 in fish fed soybean meal diets and decreased significantly (p < 0.05) beginning at day 28 in fish fed soybean meal-based diets. The haematocrit of fish fed diets D and E were significantly (p < 0.05) lower at day 28 compared to day 56. There were no significant variations in haemoglobin concentration and the leucocytes counts (p > 0.05). The proteins, blood glucose and the transaminases increased significantly (p < 0.05) along gradient of dietary inclusion and duration of feeding in the first 28 days while creatinine kinase activity, blood urea nitrogen and uric acid concentration remained significantly elevated (p < 0.05) in fish fed the soybean meal-based diets. The results of the study show juvenile L. cubie may tolerate up to 40% dietary inclusion of soybean meal as replacement for fish meal.

Distribution of metals in Labeo coubie (Ruppel, 1832) from a National Park river in Nigeria

This study assesses heavy metals distribution in body parts of Labeo coubie (African carp) fromRiver Oli, in Kainji Lake National Park as pollution index of the ecosystem. Fish parts samples (gills, muscles andvertebra bone) were prepared and specifically analyzed for the levels of Pb, Cr, Zn, Cu, Fe and Cd using Atomicabsorption spectrophotometry. The concentration of metals in the samples at different concentrations ranged from0.001±0.000 μg/g for Cd to 224.87±4.07 μg/g of Fe in the fish gill. There is significant (p<0.05) differences in the Pb,Zn, Cu and Fe concentrations across the different fish parts with gills accumulated the highest levels metals while Crlevels significantly (p<0.05) differed in the fish body parts and accumulated more in the muscles (10.75±0.15 μg/g).The mean concentrations of metal elements in the fish parts had shown some distinguish connection in its distributionswith Pb and Cu; Gills > Muscles > Vertebra bones, Fe and Zinc; Gills > Vertebra bones > Muscles while Cr wasdistributed in Muscles > Gill > Vertebra bones. However, it is revealed that Labeo coubie, a euryphagus fish probablyabsorb these metals through ingestion of contaminated food or absorption by the gills and bioaccumulate in differentfish parts. It is therefore established that River Oli is contaminated with heavy metals as presence of these metals infish is an indication of its immediate environment. Keywords: absorption, bioaccumulation, fish parts, heavy metals, pollution

Reproductive Strategy ofLabeobarbus batesii(Boulenger, 1903) (Teleostei: Cyprinidae) in the Mbô Floodplain Rivers of Cameroon

Aspects of the reproductive strategy of African carp,Labeobarbus batesii, were investigated from May 2008 to October 2009 in the Mbô Floodplain of Cameroon. Samples were collected monthly from artisanal fishermen. The total length and total body mass of each specimen were measured to the nearest mm and 0.01 g, respectively. Sex was determined by macroscopic examination of the gonads after dissection. The sex ratio was female skewed (overall sex ratio: 1 : 1.42). Females reach sexual maturity at a larger size (213 mm) than the males (203 mm). The mean gonadosomatic index ranges from0.32±0.17% to1.91±1.15%, whereas the meanKfactor ranges from0.90±1.09to1.10±0.13. These two parameters are negatively correlated. The reproduction cycle begins in mid-September and ends in July of the next year, and they are reproductively quiescent for the rest of the year.Labeobarbus batesiiis a group-synchronous spawner with pulses of synchronised reproduction spread over a long period. The mean absolute, potential, and relative fecundities are2898±2837oocytes,1016±963oocytes, and9071±7184oocytes/kg, respectively. The fecundity is higher and positively correlated with the gonad mass than with body size. Its reproductive biology suggests thatL. batesiiis suitable for pond culture.