Effect of aqua-drugs and chemicals on shrimp health and production in Khulna, Bangladesh

Present study was conducted in three different Upazilas viz., Batiaghata, Dacope and Rupsha of Khulna district, Bangladesh from August 2016 to May 2017. Data were collected through personal contact, farms and market survey and discussion with shrimp farmers and drug sellers. Farmers of the research areas used Oxolinic acid, Renamucin, Oxytetracucline, Lime, Salt, Formalin, Eco-solution, Basudin and Timsen to treat the viral, bacterial and fungal diseases. Average recovery of 55-60% and 35-40% were recorded from bacterial and fungal diseases of shrimp respectively, but there was no recovery in case of viral diseases. Shrimps of nontreated ghers were affected by WSSV, Black gill disease, Black spot disease, Zoothumnium and external fouling but almost no disease were observed in aqua drugs-treated ponds. Histological findings showed that shrimp muscles and hepatopancreas in drug treated ponds and ghers had some pathological changes like necrosis, vacuums and hemorrhages which were severe in winter season, whereas, normal structure of muscle and hepatopancreas were observed during summer season. Production of shrimp in the study areas was recorded 6916 Kg/ha in probiotics and aqua-drugs treated ponds, whereas, 543 Kg/ha in non-treated ghers. From the present study it could be concluded that aqua-drugs and chemicals have positive effect on shrimp health and production except some pathological changes in the investigated organgs of shrimp especially during winter season.

Effects of Feed Mixed with Lactic Acid Bacteria and Carbon, Nitrogen, Phosphorus Supplied to the Water on the Growth and Survival Rate of White Leg Shrimp (Penaeus vannamei) Infected with Acute Hepatopancreatic Necrosis Disease Caused by Vibrio parahaemolyticus

This study aimed to evaluate the growth, survival rate, and resistance to acute hepatopancreatic necrosis disease (AHPND) of white leg shrimp (Penaeus vannamei) by using Lactobacillus plantarum, Lactobacillus fermentum, and Pediococcus pentosaceus mixed with feed, and at the same time supplying CNP in a ratio of 15:1:0.1 to the water. As a result, the treatments that shrimp were fed with feed containing lactic acid bacteria (LAB), especially L. plantarum, have increased shrimp growth, total hemocyte cells, granulocyte cells, and hyaline cells significantly (p < 0.05) in comparison to the control group. The supply of CNP to the water has promoted the intensity of V. parahaemolyticus effects on shrimp health and significantly decreased total hemocyte cells, granulocyte cells, and hyaline cells by 30–50% in the period after three days of the challenge, except in L. plantarum treatment, which had only a 20% decrease compared to other treatments. In CNP supplying treatments, the AHPND infected rate and mortality of shrimp were higher than those in other treatments. In summary, the supply of CNP had significantly reduced the shrimp’s immune response and promoted the susceptibility of shrimp to AHPND in both cases of use with and without LAB-containing diets.

CASE OF SHRIMP PLEOPOD NECROSIS IN TRADITIONAL PONDS THAT APPLY PROBIOTICS

Traditional ponds fail in vanname shrimp farming due to disease. Disease causing pathogens can come from the culture environment, innate from shrimp seeds, and other inputs (introduction). Observation of shrimp health condition through detection of necrosis in swimming legs which, if left unchecked, will spread to the shrimp abdominal carapace, with the characteristics of the shrimp will look flushed by taking shrimp samples, and the results are expressed in percentage or prevalence. Symptoms of loss of swimming legs and uropod from the disease, of course, will reduce the selling value of the shrimp. The study was conducted on a traditional pond in Banyuanyara Village, Sanrobone District, Takalar Regency, South Sulawesi Province. Early cases of necrosis began to be detected at week 5th and peaked at week 8th. Vanname shrimp swimming leg necrosis in traditional ponds is significantly influenced by the number of bacteria in the water, where the more bacteria there are, the lower the prevalence of vanname shrimp swimming leg necrosis.

Green water technology for the production of pacific white shrimp, Penaeus vannamei (Boone, 1931)

A study was conducted to assess the efficiency of green water culture strategy for production of Pacific white shrimp Penaeus vannamei (Boone, 1931) in high density polyethylene (HDPE) lined ponds (300 m2) for a period of 96 days. Green water from a broodstock fish pond was used for rearing shrimp in treatment ponds; whereas, filtered seawater was used for growing shrimp in control ponds, with both treatment and control in triplicates. Shrimp juveniles (specific pathogen free, SPF) of uniform size (1.74±0.46 g) were stocked at the rate of 100 nos. m-2 per pond. Feeding, water exchange, sampling and water quality analysis were done as per standard shrimp growout procedure. Shrimp health status and microbial load in culture ponds were recorded periodically. Water quality parameters did not show significant variations between control and treatment ponds. Enhanced growth, survival (19.7%) and biomass (23.3%) were observed in treatment ponds when compared to control. Significant reduction in bacterial population and improved shrimp health status were also noticed in treatment ponds. Green water culture technique reduced harmful bacterial population in culture ponds and enhanced shrimp growth, survival, health and production.