Ravi Fotedar

Dietary supplementation of mannan oligosaccharide improves the immune responses and survival of marron, Cherax tenuimanus (Smith, 1912) when challenged with different stressors

Three trials were conducted to determine the effects of mannan oligosaccharide (Bio-Mos ) on the immune responses of marron. In the first trial marron were challenged with Vibrio mimicus infection, in the second with NH3 exposure and in the third, the marron were exposed to air during a simulated live transportation trial. For V. mimicus infection and live transportation trials, marron (10.44 +/- 0.20 g and 4.44 +/- 0.20 g initial weights, respectively) were fed three different diets containing 0% (control diet), 0.2% and 0.4% Bio-Mos for 30 days and 112 days respectively before challenge, whereas for the NH3 exposure trial, marron (94 +/- 2.17 g initial weight) were reared with the control diet and 0.4% Bio-Mos diet for 42 days before exposure to NH3. Marron were examined for survival and total haemocyte count (THC), differential haemocyte count (DHC), haemolymph clotting time, bacteraemia and lysosomal membrane stability as indicators of immune responses during the course of the challenge. Survival of marron infected with bacteria and exposed to NH3, were significantly improved when fed Bio-Mos. THCs were significantly reduced in marron fed the control diet when they were infected with bacteria and subjected to live transportation while it remained unchanged in the marron fed the Bio-Mos supplemented diets. THCs of marron fed any of the diets were reduced when they were exposed to NH3 but the THCs were higher (P < 0.05) in marron fed Bio-Mos diets. Vibrio spp. in haemolymph of marron fed the control diet significantly increased when they were infected with V. mimicus and challenged with NH3 but it remained unchanged in the marron fed the Bio-Mos diets. Haemolymph clotting time was higher in marron fed the control diets when subjected to live transportation and 3 days of exposure to NH3. After 96 h infection marron fed the Bio-Mos diets had longer NRR time than those fed the control diet. All the findings demonstrated the ability of Bio-Mos to improve the survival, health status and immunity of marron under the bacterial infection and stress conditions caused by air and NH3 exposures.

Effects of mannan oligosaccharide dietary supplementation on performances of the tropical spiny lobsters juvenile (Panulirus ornatus, Fabricius 1798).

The effects of dietary mannan oligosaccharide (MOS) (Bio-Mos, Alltech, USA) on the growth, survival, physiology, bacteria and morphology of the gut and immune response to bacterial infection of tropical rock lobsters (Panulirus ornatus) juvenile were investigated. Dietary inclusion level of MOS at 0.4% was tested against the control diet (trash fish) without MOS inclusion. At the end of 56 days of rearing period, a challenged test was also conducted to evaluate the bacterial infection resistant ability of the lobsters fed the two diets. Lobster juvenile fed MOS diet attained 2.86 +/- 0.07 g of total weigh and 66.67 +/- 4.76% survival rate which were higher (P < 0.05) than the lobsters fed control diet (2.35 +/- 0.14 g total weight and 54.76 +/- 2.38% survival rate, respectively) thus providing the higher (P < 0.05) specific growth rate (SGR) and average weekly gain (AWG) of lobsters fed MOS diet. Physiological condition indicators such as wet tail muscle index (Tw/B), wet hepatosomatic index (Hiw) and dry tail muscle index (Td/B) of the lobsters fed MOS supplemented diet were higher (P < 0.05) than that of the lobsters fed the control diet. Bacteria in the gut (both total aerobic and Vibrio spp.) and guts absorption surface indicated by the internal perimeter/external perimeter ratio were also higher (P < 0.05) when the lobsters were fed MOS diet. Lobsters fed MOS diet were in better immune condition showed by higher THC and GC, and lower bacteraemia. Survival, THC, GC were not different among the lobsters fed either MOS or control diet after 3 days of bacterial infection while bacteraemia was lower in the lobsters fed MOS diet. After 7 days of bacterial infection the lobsters fed MOS diet showed higher survival, THC, GC and lower bacteraemia than the lobsters fed the control diet. The experimental trial demonstrated the ability of MOS to improve the growth performance, survival, physiological condition, gut health and immune responses of tropical spiny lobsters juveniles.

The Effect of Potassium Concentration in Inland Saline Water on the Growth and Survival of the Western King Shrimp, Penaeus latisulcatus Kishinouye, 1896

Abstract The survival, growth, and condition of the western king shrimp, Penaeus latisulcatuswere measured for 42 days when grown in marine water and inland saline water with four different concentrations of potassium: 100%, 80%, 60% or 40% of the concentration of potassium in marine water (IS100, IS80, IS60, and IS40). Shrimp survival and cannibalism frequency decreased with decreasing potassium concentration, with final shrimp survival in IS100 significantly higher (P < 0.05) than in IS60 and IS40 and significantly higher (P < 0.05) in MW and IS80 than in IS40. Specific growth rate (SGR), moult increment, and diet ingestion rate of shrimp were significantly higher (P < 0.05) in shrimp grown in marine water than the other water types. At the conclusion of the trial, exoskeleton mineral content of shrimp in IS100 and IS80 was significantly higher (P < 0.05) than in IS60 and IS40. Tail muscle moisture content of shrimp in IS60 and IS40 was significantly higher (P < 0.05) than in the other water types, suggesting a depletion of tail muscle energy reserves in IS60 and IS40. This trial demonstrates the necessity of fortifying potassium-deficient inland saline water to allow the culture of western king shrimp. Furthermore, a potassium concentration greater than approximately 76% of that in marine water and a Na/K ratio of less then 39 appear to be necessary to maintain a comparable level of shrimp survival, as in marine water. However, the slower growth and reduced molt increment of shrimp in inland saline water with 100% and 80% potassium compared to shrimp in marine water demonstrates the presence of other limiting factors.

The use of customised probiotics in the cultivation of western king prawns (Penaeus latisulcatus Kishinouye, 1896)

This study presents a comprehensive review of probiotics usage in aquaculture with a specific emphasis on our research series on the effectiveness of the customised probiotics, Pseudomonas synxantha and Pseudomonas aeruginosa on the cultivation of western king prawns, Penaeus latisulcatus. These customised probiotics resulted from tests using five inhibition test methods between the bacteria isolated from two commercial probiotic products and Vibrio spp. isolated from western king prawns and other aquatic animals. The results proved the suitability and safety of these probiotics in the cultivation of western king prawns as they conclusively met all the essential requirements for appropriate probiotics. These probiotics have shown similar beneficial effects as the common prebiotics, Bio-Mos and beta-1,3-d-glucan on the growth, survival and immune responses of the prawns. The supplementation of probiotics with the formulated feed was more efficacious and more practical than direct application into the rearing media. The prawns exposed to the combined probiotics were healthier than those exposed to the individual probiotics. P. aeruginosa was more effective for improving prawn health than P. synxantha. The probiotic-fed prawns were not influenced by Vibrio harveyi at 10(3) CFU ml(-1) for 36 h of challenge. In conclusion, these customised probiotics can be used as appropriate probiotics and as a suitable replacement of antibiotics, for disease control in western king prawn aquaculture.

Effects of dietary β – 1,3 – glucan on the growth, survival, physiological and immune response of marron, Cherax tenuimanus (smith, 1912)

Six isonitrogenous and isocalorific diets supplemented with five different levels of beta-1,3-glucan (0.08%, 0.1%, 0.2%, 0.4% and 0.8%) were formulated and tested for marron (Cherax tenuimanus) growth, survival, organosomatic indices, osmoregulatory capacity and immunological parameters (total and differential haemocyte counts, haemolymph clotting time and bacteraemia). The sixth diet without any beta-1,3-glucan was used as a control. Each diet was provided to 18 marron (0.47 +/- 0.02 g initial weight) replicated 3 times in individual 250 L fiberglass cylindrical tanks. Each tank was provided with a biological filtration recirculating water system. After 84 days of culture, the survival and yield were higher in the marron fed 0.1% beta glucan supplemented diet. The different levels of beta glucan did not alter any of the physiological parameters of marron. However, dietary supplementation with beta glucan resulted in significantly higher (P < 0.05) total haemocyte count (THC) and granular cells. The bacteraemia rank was lower in all diets having beta glucan supplemented with more than or equal to 0.1% compared to the control and 0.08% beta glucan supplemented diets. Results suggest that dietary beta-1,3-glucan at a minimum concentration of 0.1-0.2% can improve the immune system of marron.

Dietary organic selenium improves growth, survival and resistance to vibrio mimicus in cultured marron, cherax cainii (Austin, 2002)

To determine the effects of dietary organic selenium (OS) supplementation on the growth performance and immune competence of marron, Cherax cainii (Austin, 2002), a group of marron were fed 0.2 g kg(-1) of Sel-Plex(®) supplemented basal diet and then compared with another group (control) of marron fed basal diet without any supplementation. After 90 days of feeding, final weight, average weekly gains (AWG), relative gain rate (RGR), specific growth rate (SGR), survival, total and differential haemocyte counts (THC and DHC), were compared between the two groups. Surviving marron from each group were then divided into three sub-groups (three tanks per sub-group with seven marron per tank); (1) first sub-group was injected with 20 μL of 3.24 × 10(6) cfu Vibrio mimicus; (2) the second sub-group was injected with 20 μL normal saline and (3) the third sub-group was not subjected to injection and became the control group. THC, DHC, neutral red retention time (NRRT) and Vibrio ranks of post-injected marron were evaluated for 96 h, at every 24-h interval. The results showed that after 90 days of feeding, final weight, AWG, RGR, SGR, survival, THC, proportion of hyaline cells of OS-fed marron were significantly higher (P < 0.05) than the control group, whereas proportion of granular and semigranular cells were not affected by dietary OS. After challenging with V. mimicus, survival rate of marron without dietary OS significantly decreased (P < 0.05) as compared to the control group of marron. THC of marron in all sub-groups were significantly reduced (P < 0.05) after the challenge. However, THC and granular cells of sub-groups fed OS were higher than other sub-groups. Vibrio ranks and NRRT of marron fed OS were significantly lower and slower, respectively, than marron fed without OS. These findings demonstrated the benefits of OS inclusion in the marron diet in terms of growth, health and disease resistance.

The Effects of Air Exposure on Hemolymph Osmoregulatory Capacity of Brown Tiger Shrimp, Penaeus esculentus, and Western King Shrimp, Penaeus latisulcatus, Reared at Different Salinities

Abstract Hemolymph osmolality and osmoregulatory capacity (OC) of brown tiger shrimp, Penaeus esculentus (0.94±0.04 g mean initial weight) and western king shrimp, P. latisulcatus (5.37±0.10 g mean initial weight) from four salinities (10, 22, 34 and 46 ppt) were determined following 7, 14 and 21 minutes of air-exposure. Hemolymph osmolality of both species increased with increasing salinity. Isosmotic points of brown tiger shrimp calculated from regression lines between hemolymph and medium osmolality were 30.9, 31.9, 32.1 and 31.1 ppt at 0, 7, 14, and 21 minutes of air-exposure, respectively. Isosmotic points of western king shrimp were 33.8, 33.3, 32.8 and 33.1 ppt at 0, 7, 14, and 21 minutes air-exposure, respectively. OC of brown tiger shrimp at salinity of 34 ppt did not change when exposed to air for any length whereas OC of shrimp at other salinities (10, 22 and 46 ppt) were significantly different (P < 0.05) when exposed to air for 21 minutes. OC of western king shrimp at salinity 10 ppt was reduced (P < 0.05) when exposed to 14 and 21 minutes of air when compared to control and 7 minutes of air exposure. The results indicate that both species spent less energy (P < 0.5) for osmoregulation from 30 to 34 ppt. Furthermore, salinities 10 and 46 ppt were unsuitable for rearing brown tiger shrimp and salinity 10 ppt was unsuitable for growing western king shrimp.

Effects of the dietary supplementation of mixed probiotic spores of Bacillus amyloliquefaciens 54A, and Bacillus pumilus 47B on growth, innate immunity and stress responses of striped catfish (Pangasianodon hypophthalmus).

ABSTRACT The study used the mixed probiotics of Bacillus amyloliquefaciens 54A and B. pumilus 47B isolated from striped catfish (Pangasianodon hypophthalmus) intestine aiming to stimulate growth performance, innate immunity, stress tolerance of striped catfish. The average weight gain (AWG), specific growth rate (SGR), and feed conversion ratio (FCR) were analyzed after fish were fed the mixture of probiotics (B. amyloliquefaciens 54A and B. pumilus 47B) at concentrations of 1 × 108, 3 × 108, and 5 × 108 CFU g−1 feed for 90 days. Immunity parameters, survival rate of fish challenged with Edwardsiella ictaluri and ammonia tolerance were also investigated. The amounts of B. amyloliquefaciens and B. pumilus were counted and identified by specific primer pairs of Ba1‐F/Ba1‐R, and 16‐F/Bpu‐R to confirm the presence of probiotics in fish intestine. The AWG (476.6 ± 7.81 g fish−1) of fish fed probiotics at 5 × 108 CFU g−1 was significant higher than the control (390 ± 25.7 g fish−1) after 90 days of feeding, but there was no significant (P > 0.05) effect of probiotics on FCR and SGR. Fish fed diet containing probiotics at 5 × 108 CFU g−1 also expressed resistance to E. ictaluri infection and higher immune parameters such as phagocytic activity, respiratory bursts, and lysozyme activity than the control. Stress response with ammonia showed significantly lower mortality rate (25%, 20% and 27%) of fish fed probiotics at all three levels of 1, 3 and 5 × 108 CFU g−1 than the fish fed control diet (75%). The study also demonstrated that the probiotics survived in the intestine of striped catfish after 90 days of feeding. Therefore, the dietary supplementation of a mixture of B. amyloliquefaciens and B. pumilus at 5 × 108 CFU g−1 can be used to improve the health and growth rate of striped catfish. HIGHLIGHTSThe spores of B. amyloliquefaciens 54A and B. pumilus 47B were first applied as probiotics in striped catfish.Dietary supplementation with B. amyloliquefaciens 54A and B. pumilus 47B for 90 days enhanced fish growth.Innate immunity of striped catfish were stimulated after feeding B. amyloliquefaciens 54A and B. pumilus 47B for 90 days.The mixture of B. amyloliquefaciens 54A and B. pumilus 47B in the diet enhanced disease resistance and stress tolerance.Colonization of B. amyloliquefaciens 54A and B. pumilus 47B in the intestine of striped catfish was observed.

Prebiotic Mannan Oligosaccharide Diet Improves Health Status of the Digestive System of Marron, Cherax tenuimanus (Smith 1912)

The aim of this experiment was to determine the effects of dietary supplementation with mannan oligosaccharide (MOS; BioMos, Alltech, USA) on the gut microbiota and histology of marron, Cherax tenuimanus. Marron were fed six different diets supplemented with 0%, 0.05%, 0.1%, 0.2%, 0.4%, and 0.8% of MOS for a duration of 112 days. Total bacteria in the gut were highest when marron were fed diets which included 0.1% to 0.4% BioMos, whereas total bacteria/Vibrio spp. ratio was highest in the marron fed 0.4% BioMos diet only. The marron fed 0.2% and 0.4% BioMos diets showed normal morphology and higher densities of microvilli, and thicker layer of gut epithelium than other inclusion rates. The results suggest that application of 0.2% to 0.4% of MOS in the diet improves digestive system health in marron.

A review of probiotics in shrimp aquaculture.

Development of shrimp aquaculture has been associated with increases in infectious diseases and environmental degradation. An effective alternative to chemicals and antibiotics used for the prevention of these problems is to administer probiotics into the rearing system. Three bacterial genera, Bacillus, Vibrio, and Pseudomonas, are commonly administered as probiotics in shrimp aquaculture. Candidate probiotics are species specific and need to be tested for their effectiveness for certain species in in vitro and in vivo. Supplementation into feed is more effective in conveying probiotics into animals compared to direct application into rearing systems. Overdosage or prolonged administration of probiotics can induce immunosuppression. A cell-density of 105 colony-forming units (CFU) per ml is widely recommended. A combination of probiotics results in better outcomes for the host than individual probiotics. Probiotics improve water quality while reducing pathogenic bacteria. Probiotics show positive effects through an improvement in the physiological and immune responses of shrimps. Probiotics are increasingly becoming important and more common in any organic shrimp farming.