R. Karthik

Bio: R. Karthik is an academic researcher from AMET University. The author has contributed to research in topics: Litopenaeus & Penaeus monodon. The author has an hindex of 6, co-authored 13 publications receiving 99 citations.

Effective removal of Methylene Blue dye from water using three different low-cost adsorbents.

Abstract: Water pollution has become an environmental problem worldwide as well as local. Dyes represent the raw material in textile, leather, paper and plastic industries and a pollutant or toxic waste in the untreated effluents discharged out from these industries. The adsorption process is one of the most efficient methods for the removal of dye from waste water. The present laboratory model study was carried out to check the effect of three different low-cost adsorbents (such as banana fibre, coconut fibre and sawdust) and their adsorption capacity of Methylene Blue dye from water. While checking with different initial dye concentration for all the adsorbents, the maximum adsorption was observed in 250 mg l−1, and the same concentration followed for further optimization. For optimization, one parameter at a time method was followed at different pH (3.0, 5.0, 7.0, 9.0, and 11), temperature (25, 30, 35, 40, and 45°C), adsorbent dosage (1, 3, 5, 7, and 10%) and contact time (30, 60, 90, 120, 150, 180, and ...

Effectiveness of Lactobacillus sp (AMET1506) as Probiotic against Vibriosis in Penaeus monodon and Litopenaeus vannamei Shrimp Aquaculture

Abstract: CFU g-1 of Lactobacillus sp (AMET1506), and the control tanks were fed with a control diet. Shrimp in all the groups were fed twice daily at 5.0% of biomass and the water temperature was maintained at 28 ± 1°C. After 30 days of culture, shrimp in all the control and experimental tanks were exposed to V. harveyi (105 CFU ml-1) for 10 days. During the experiment, the accumulated mortality of the shrimp and the microbial load in the shrimp and culture water was recorded. Among that, the shrimp P.monodon treated with Lactobacillus sp AMET1506 resulted in 6% final mortality as compared to 80% in the control group and in L.vannamei treated with Lactobacillus sp AMET1506 resulted in 12% final mortality as compared to 100% in the control group. Based on these results, the work has suggested to use this potential strain Lactobacillus sp AMET1506 as a probiotic in shrimp aquaculture feeds to improve the shrimp microbiota (GIT) and also to control the vibriosis in shrimp aquaculture.

Efficacy of Probiotic and Nitrifier Bacterial Consortium for the Enhancement of Litopenaeus Vannamei Aquaculture

Abstract: Shrimp farming is one of the most important aquaculture practices worldwide. In general, the excess feed and faecal matter deposited in the bottom of the pond undergo ammonification and result in excess of ammonia formation in pond water and sediment. In addition, eutrophication in the culture system/pond can cause stress to the animals and ultimately end with microbial diseases.

Crop Rotation as a Better Sanitary Practice for the Sustainable Management of Litopenaeus vannamei Culture

Abstract: In the present study, finfishes (Mugil cephalus and Chanos chanos) were cultured between crops of Litopenaeus vannamei shrimps for crop rotation and the reduction in the incidence of shrimp diseases was observed. The fish seeds of 5-7 g individual weight were collected from the wild and required numbers were sorted out and stocked in the ponds at the rate of 7000 and 8000 numbers of Mugil cephalus and Chanos chanos, respectively in 1.3 ha. For shrimp culture, the seeds were purchased from a reputed hatchery and were stocked at a density of 7.7 shrimps m–2. In the control pond, the shrimps were stocked at the same density. The first crop was a fish culture experiment for 6 months followed by a shrimp culture experiment for 4½ months in one pond and the other pond was used as control and two shrimp culture experiments were carried out. During the culture period, the water quality parameters such as, temperature, salinity, pH, transparency, dissolved oxygen, ammonia, nitrite, nitrate, phosphate, silicate and the microbial load were analyzed. While comparing the performance of shrimps in the experiment pond and control pond, experimental shrimp pond yield was interesting with 695.3 kg of more production, similarly survival rate was 25% higher, Average Body Weight (ABW) was 2.9 g higher and Average Daily Growth (ADG) was 0.16 g higher for 90 days of culture. The results of the study have clearly established the advantages of crop rotation with fish than continuous culture of shrimps in the same system.

Attenuation of Negative Impacts by Micro Algae and Enriched Artemia Salina on Penaeus Monodon and Litopenaeus Vannamei Larval Culture

Abstract: Providing a specific pathogen free (SPF) shrimps to the farmers is a big challenge that must be addressed to meet the demand. In general, microalgae are utilized in aquaculture as a live feed for the shrimps. However their importance in the attenuation of negative impacts of pathogenic microbial load, eutrophication and promotion of shrimps growth has to be delineated by experimental investigations to justify the above specific pathogen free shrimps. The present study was carried out to investigate the feeding of five different microalgae and algae enriched Artemia salina. Nauplii on digestive enzyme activity, growth, survival rate, microbial load on Penaeus monodon and Litopenaeus vannamei from Zoea to post larvae (20 stages) and other water quality. Microalgae such as Isochrysis galbana, Cheatoceros calcitrans, Tetraselmis sp, Chlorella sp and Nannochloropsis sp were obtained from AMET Microbial Culture Collection Centre, Department of Marine Biotechnology, AMET University. Penaeus monodon and Litopenaeus vannamei at PL 20 stage showed maximum protease and amylase (digestive enzyme) activity, maximum length and survival rate when fed with Artemia salina Nauplii enriched with C. calcitrans followed by Chlorella sp. On studying the water quality parameters such as, pH, temperature, salinity, dissolved oxygen and ammonia it was found better in tank II where the shrimps were fed with Artemia salina enriched with C. calcitrans. Regarding the vibrio load at different stages of P. monodon and L. vannamei larvae and cultured water it was comparatively lower in tank II where the shrimps were fed with Cheatoceros calcitrans and enriched Artemia salina than other groups.

Gut Microbiota and its Modulation for Healthy Farming of Pacific White Shrimp Litopenaeus vannamei

Abstract: The Pacific white shrimp Litopenaeus vannamei is the most important crustacean species in aquaculture, accounting for 70% of the total shrimp production in the world. In the past decade, development of the shrimp industry has been greatly impeded by disease prevalence, poor growth in low salinity inland water, dietary use of plant ingredients, and antibiotic overuse. The animal gut is a vital organ, and most of the gut functions, such as the functions of immunity, health regulation and nutrient absorption, are achieved by bacterial metabolism in the gut. Therefore, understanding the role of the gut microbiota of L. vannamei is important for improving the performance and production of L. vannamei in aquaculture. This paper summarizes the recent advancements in research on the composition of the gut microbiota of L. vannamei, the factors that influence the microbiota, and nutritional manipulation of the gut microbiota. In addition, based on the review, current problems are raised and future studies ...

Probiotics and competitive exclusion of pathogens in shrimp aquaculture

Abstract: Probiotics, live microorganisms that, when administered in adequate amounts, confer a health benefit on the host, offer an alternative to antibiotics and have become popular among shrimp farmers for use in the regulation of pond water quality, promotion of shrimp growth and the prevention of disease. Most shrimp probiotics are selected for testing based on their ability to competitively exclude pathogens through bacterial antagonism assays, although the mechanisms of pathogen exclusion are rarely investigated. In this review, we provide a comprehensive overview of the mechanisms of competitive exclusion (interference and exploitation competition) by species screened and subsequently identified as shrimp probiotics based on their ability to inhibit the growth of pathogenic bacteria in vitro. We show that the current methods used to identify potential probiotics preferentially select for interference-based competitive mechanisms and may overlook the potential of many species to be considered a probiotic. Furthermore, we show that the efficiency of a probiotic in vivo may be improved by considering the suitability of competitive strategies to shrimp farming conditions. We highlight important limitations and future directions for the screening and identification of probiotics in shrimp aquaculture, to aid in the development of effective and sustainable microbial management strategies.