Effects of different levels of pinus tabulaeformis pollen on growth and ammonia stress resistance of milkfish fry (Chanos chanos)

Abstract

The present preliminary study investigated the effects of different levels of dietary pine pollen from Pinus tabulaeformis Carr. on the growth and efficiency performance and ammonia stress resistance of milkfish fry (Chanos chanos). After acclimation, 600 milkfish fry with average body weight of 0.02 g were stocked in 15, 50L tanks (40 fish per tank). A control diet (without pine pollen, PP) and 4 experimental diets containing various levels of PP, namely, 0, 1.3, 2.6, 3.8, and 5.1 g/kg were prepared and given for 60 days. At termination of the experiment, milkfish were subjected to ammonia stress. Results showed that milkfish fed diets containing various levels of pine pollen exhibited significantly higher weight gain (WG), specific growth rate (SGR), protein efficiency ratio (PER), and better feed conversion ratio (FCR) than fish fed the control diet. Survival rates of the milkfish during the feeding trial were not significantly different among dietary treatments (p>0.05). A separate experiment was conducted in which milkfish were subjected to ammonia stress test following feeding of experimental diets for 2 weeks. Results showed that milkfish fed with diets containing 2.6 to 5.1 g/kg exhibited significantly higher survival (p<0.05) than did those fed with the control diet and with the diet containing 1.3 g/kg PP. The optimal inclusion level of pine pollen was estimated using values for SGR and FCR fitted to quadratic model to be 3.0 g/kg. The results of this study indicated that pine pollen could be used as a dietary additive for the young milkfish to enhance growth and immune response to dissolved ammonia.