Effects of salinity and alkalinity on growth and survival of all-male giant freshwater prawn (Macrobrachium rosenbergii De Man, 1879) juveniles

All-male giant freshwater prawns (AMGFPs) have been a popular crop cultivated in the Mekong Delta, Vietnam, due to their proven production efficiency compared to all-female or mixed-sex prawn cultures. However, the crucial water quality factors impacting AMGFP aquaculture efficiency have yet to be elaborately investigated. Two separate experiments were randomly arranged with three replicates to evaluate the effects of salinity or alkalinity on the growth and survival of AMGFP juveniles during the grow-out period. The results show that the prawn survival rate in the salinity range of 0–15‰ varied from 66.1 to 74.8％ and in a salinity range of 0–5‰ was relatively low compared to the range of 10-15‰; however, the difference was not significant among salinities after 90 days of culture (p > 0.05). All the prawn growth performance parameters significantly decreased with increasing salinities of 0, 5, 10, and 15‰ after 30, 60, and 90 days of culture (p 0.05), and both were significantly higher than those at salinities of 10 and 15‰ (p < 0.05) after 90 days of culture. In addition, the survival rate reached 82.5–84.4％ and did not significantly differ among alkalinities of 80, 100, 120, 140, and 160 mgCaCO3 L−1. However, the growth performance parameters and yield of AMGFPs at an alkalinity of 160 mg L−1 were significantly higher than those at lower alkalinities (80, 100, 120, and 140 mg CaCO3 L−1) after 90 days of culture. Therefore, it is recommended that a salinity range of 0–5‰ and alkalinity of 160 mgCaCO3 L−1 is optimal for the growth-out culture of AMGFP juveniles

Growth and survival rates of domesticated and non-domesticated breeding stocks of Penaeus monodon Fabricius, 1798 cultured in ponds and tanks

Sourced breeders from domesticated broodstocks have played an essential role in the steady development of shrimp culture in many countries. In the present study, two experiments were performed in Tra Vinh province, Vietnam, to compare the culturing benefits of sourced breeding stocks from domesticated and non-domesticated Penaeus monodon broodstock. The first 90-day experiment was randomly arranged with three repetitions in six earthen ponds (1,500–2,000 m2). Experimental shrimp (PL12) were stocked at a density of 20 ind. m−2. The second experiment was randomly designed with three repetitions in six composite tanks (6.0 m3). PL15 of experimental shrimp were cultured at a density of 30 ind. m−2 for 120 days. Grobest pellet feed (40 % protein) was used in both experiments. At experiment termination, the mean weight (26.09 g) and length (15.68 cm) under pond culture, as well as respective values of 15.57 g, and 13.21 cm under tank culture, for D-shrimp were significantly higher than those of W-shrimp (p<0.05). Similarly, the survival rate (84.33 %), FCR (0.98), and yield (3,558 kg ha−1) under pond culture, as well as the survival rate (87.59 %) and yield (470 g m−3) under tank culture, of D-shrimp were significantly better than those of W-shrimp (p<0.05). These results prove that the grow-out culture of shrimp postlarvae from domesticated broodstocks resulted in superior performance to those from wild broodstocks