Aspects of the reproductive biology of hatchery-raised Clarias gariepinus I: fecundity

Abstract

The fecundity of four batch weights (10 samples each) o gravid Clarias gariepinus weighing 60 ± 0.17159 g 125 ± 0.15092 g 250 ±0.20683 g and 500 ± 0.15670 g raised from the hatchery was investigated The paired ovary of each fish was dissected out, weighed (g) and its length measured (mm). Each paired ovary was stored n a solution of 1 % formalin in 0 6 % saline solut on for at least 3 weeks for the solution to harden the eggs and remove egg clumping. After 3 weeks, each paired ovary was torn apart on a 2 mm mesh circular fabricated sieve over a stream of water. The eggs passed through the 2 mm mesh sieve into a receptacle. Sub sample of the eggs from each paired ovary was taken, counted and all the eggs in each paired ovary were determined thereafter by volumetric method. The tota fecund y of 40 gravid f sh stud ed ranged rom 6,450 to 71,450 eggs per f sh. The mean fecundities of the 60 g 125 g, 250 g and 500 g f sh were 8,501.9 ± 295.5, 13,364.0 ± 1734.3, 41 087.9 ± 12258.1 and 51,186.0 ± 13851.0 eggs respect vely. The relationships between fecundity and fish weight (FW) (n = 40, r = 0.8761), f sh ota leng h (TL) (n= 40, r = 0.8266), f sh ovarian we ght (OW) (n = 40, r = 0.7609), fish ovar an length (OL) (n = 40, r = 0.7236), gonadosomatic index (GSI) (n = 40, r = 0.5992) and f sh cond t on factor (K) (n = 40, r = 0.9046) obta ned were linear and positive and the condit on factor appeared to be the best predictor of fecundity in C. gariepinus studied. The higher fecundity o C. gariepinus (range: 6,450 to 71 450) obta ned from th s study when compared w th the range of 9,000 to 25,000 earlier reported from the wild stock indicates that hatchery-raised C. gariepinus is more fecund than the wild fish in the Anambra area of the sub-region. Therefore, hatchery-raised C. gariepinus appears to be better for fish breeding in fingerl ngs production than the wild fish.

Effect of Moringa oleifera, Bacillus amyloliquefaciens, and Their Combination on Growth Performance, Digestive Enzymes, Immunity, and Microbiota in Nile Tilapia (Oreochromis niloticus)

“…During feeding, it was observed that the fish showed a low level of initiative towards eating the feed supplemented with M. oleifera (MO-CON, MO-Ba). We hypothesize that this can be attributed to the characteristic odor of M. oleifera, which may result in poor palatability of the feed [29]. The taste reception is important for the choice of food selected by fish.…”

Assessment of fecundity of Brycinus macrolepidotus in Akomoje water reservoir, Abeokuta, South West, Nigeria

“…The strong positive correlations recorded between fecundity and total length in this study indicated that total length can be used to determine the fish's potential egg production. However, Egwui et al (2007) reported that in Clarias gariepinus (Burchell, 1822), fecundity was directly correlated with body weight (r=0.7609) and also with standard length (r=0.8266). The mean absolute fecundity which was highest in the wet months indicated that the peak of the species spawning period was in the wet season.…”

Growth performance and nutritional impact of Moringa oleifera leaf extract as supplemental diets in the juvenile pacific white shrimp (Penaeus vannamei)

“…To ensure the well-being of the shrimp during their growth phase, aquaculturists have formulated an economical and nourishing food regimen that includes the usage of moringa (Moringa oleifera). Moringa represents a compelling substitute, not solely because of its costeffective and environmentally friendly antimicrobial characteristics with minimal adverse effects, but also because it improves growth performance [4]. This study explores the utilization of moringa to enhance the growth performance, survival rate, and feed conversion ratio of these shrimps.…”