Evaluation of artificial feeds for shrimp (Penaeus monodon) production in brackishwater ponds

Abstract only.The experiment was conducted in fifteen 500-m2 brackishwater ponds to determine the response of Penaeus monodon juveniles fed with various artificial diets. Five treatments with three replicates each were: two commercial feeds containing 45% and 40% crude protein (treatments I and II), two experimental diets formulated to contain 35% crude protein (treatments III and IV) and control, without feeding (treatment V). Shrimp were fed twice daily at feeding rates based on shrimp consumption. Highest mean harvest weight was attained in treatment I (23.47 g) > III (19.25 g) > II (18.86 g) > IV (11.29 g) > V (9.27 g). Statistical analysis showed that differences in growth were significant at 5% probability level. However, growth in treatments I, II and III are comparable, also growth in treatments II, III and IV. Growth in treatments I, II, III and IV was significantly different from treatment V. Highest mean survival was attained in treatment III (91.82%) > I (88.93%) > II (86.95%) > IV (83.62%) V (82.62%). Statistical analysis showed no significant differences among treatments at 5% probability level. Projecting on a hectare basis, mean yield for each treatment was: I (628.37 kg) > II (496.35 kg) per crop in 120 days culture. Good yield was attributed to provision of formulated feeds, use of pumps in addition to tidal change for water exchange and control of predators, and pest eradication through proper pond preparation

Growth and survival of Penaeus monodon postlarvae with different feeding regimes and stocking densities in earthen brackishwater nursery ponds

Abstract only.The effect of different stocking densities (50, 100 and 150/m2) and two feeding regimes (natural food, consisting mainly of lablab, and natural food plus artificial diet) on the growth and survival of Penaeus monodon postlarvae (PL4 to PL5) were evaluated in eighteen 40 m2 earthen brackishwater nursery ponds using tidal water exchange for a period of 45 days. Results of the experiment indicated that the effect of different stocking densities was highly significant (P<0.01) on growth but not on survival for the two feeding regimes. Likewise, no interaction effect was discerned. Shrimps given artificial feed (Treatments II, IV and VI) obtained higher mean weight gains of 1.55, 1.17 and 1.05 g, respectively, than those that were not given artificial feed (I-1.44 g, III-0.92 g, and V-0.66 g). Similarly, those reared with artificial feed attained better survival of 41.62% (II), 67.44% (V) and 52.14% (VI) compared to shrimp that were not given artificial feed (I-42.53%, III-54.61% and V-46.90%). An exploratory economic study showed that the nursery operation gave promising results in all treatments. High rate of investment (ROI) was obtained to give a safe margin for the risk involved in this kind of business. Among all treatments, treatment V had the highest ROI of 693% and shortest payback period of 0.19 years