EFFECT OF BACULOVIRUS-PENAEI ON GROWTH AND SURVIVAL OF EXPERIMENTALLYINFECTED POSTLARVAE OF THE PACIFIC-WHITE SHRIMP, PENAEUS-VANNAMEI

In a series of experiments conducted to investigate age and size-depen dent effects of the baculovirus BP on postlarvae of the Pacific white shrimp, Penaeus vannamei, six groups of specific pathogen-free shrimp of different ages (mysis 2-3 through PL 25) were exposed to the virus and cultured for 15 to 21 days. All BP-exposed groups of early postlar vae (PL 9 or younger) became heavily infected within 2-5 days of initi al exposure to the virus, and some of those groups experienced high mo rtalities compared to the noninfected controls. Postlarvae that surviv ed the infection had highly variable and significantly reduced growth, as determined by dry weight, compared to controls. Exposure of older postlarvae to BP produced a high prevalence of infection, but with lit tle effect on either survival or growth. One group of shrimp exposed t o BP at PL 9 was cultured for 49 days. Postlarvae that survived the in fection were significantly smaller than the noninfected controls for t he first 4 weeks following exposure to the virus; however, the effect of BP on long-term growth of infected postlarvae appeared minimal. To determine the effect of BP on nutritionally stressed shrimp, groups of noninfected and previously infected postlarvae (PL 13-14) of similar size were deprived of food for 10 days. Less than 2% of the infected p ostlarvae survived the 10-day starvation period compared to 52% surviv al of the noninfected postlarvae. (C) 1994 Academic Press, Inc.