Zoology

Permanent URI for this collection

https://hdl.handle.net/10530/477

Browse

Browsing Zoology by Author "Jerling, H.L."

Now showing 1 - 1 of 1
  • Thumbnail Image
    Item
    Effect of dietary protein level, feeding frequency and amount of food offered on growth and gastric evacuation of Oreochromis mossambicus fry
    (University of Zululand, 2012) Luthada, Rendani Winnie; Jerling, H.L.
    Excess protein in fish diet may be wasteful and unnecessarily expensive. Furthermore, when fish are fed insufficiently or excessively, their growth or feed efficiency may decrease, resulting in increasing production costs and water quality deterioration. Therefore this study was conducted to determine the optimum dietary protein level, feeding frequency and feeding rate on growth, gastric and intestinal evacuation of O. mossambicus fry under hatchery conditions, in order to reduce the production costs while optimizing growth rate. Diets contained 20%, 30%, 35%, 40% and 45% protein levels, feeding frequency of once, twice, thrice, four times and five times per day and feeding rates of 10%, 15%, 20%, 25% and 30% body weight per day were tested in separated experiments conducted in a temperature and light cycle controlled environmental room. The results indicated that both dietary protein level and feeding frequency had a significant effect on weight gain, specific growth rate and gross food conversion ratio (ANOVA, P<0.05) but not survival rate (ANOVA, P>0.05). Feeding rate had a significant effect on weight gain and gross food conversion ratio (ANOVA, P<0.05) but not on specific growth rate and survival rate (ANOVA, P>0.05). A diet containing 30% protein level, feeding frequency of four times per day and 15% of the fry body weight per day were the optimal levels obtained from the growth experiments. Dietary protein level had a significant effect on gastric and intestinal evacuation (ANOVA, P<0.05); feeding frequency had a significant effect on intestinal evacuation rate and time (ANOVA, p<0.05) only but not on gastric evacuation rate and time (ANOVA, P>0.05), while feeding rate had no significant effect on both gastric and intestinal evacuation rate and time (ANOVA, P>0.05). The optimum levels obtained in gastric and intestinal evacuation are 40% dietary protein level, feeding frequency of twice per day and a feeding rate of 15% body weight per day.
University of Zululand