Average Specific Growth Rate Research Articles

Growth performances and nutrient compositions of pabda Ompokbimaculatus (Bloch, 1797) grown in recirculating and closed aquaculture systems

This study evaluated the growth performances and nutrient compositions of pabda Ompok bimaculatus (Bloch, 1797) in a recirculating aquaculture system (RAS) and a closed aquaculture system (CAS). The average daily weight gain (ADG) and specific growth rate (SGR) of pabda in RAS (ADG: 0.18 g/d; SGR: 3.40 %/d) was 3.61- and 1.41-folds higher than that of the CAS (ADG: 0.05 g/d; SGR: 2.40 %/d). Fish had significantly higher level of PUFA (Poly-unsaturated fatty acid) in CAS (41%) than in RAS (33%). The ratio between omega-3 and omega-6 fatty acids in RAS and CAS were 0.73 and 0.69, respectively. This study’s results have demonstrated that the culture of pabda in RAS is more suitable than CAS in terms of growth.
 J. Asiat. Soc. Bangladesh, Sci. 47(1): 1-12, June 2021

Influence of Heavy Metals on the Growth of Chlorella vulgaris

Growth inhibition of chromium (Cr), cadmium (Cd) and lead (Pb) to fresh water microalga Chlorella vulgaris (C. vulgaris) FACHB-8 was examined. These results demonstrated that the concentration level (EC50 value) of three heavy metals (Cr, Cd and Pb) could be utilized as an indicator for evaluating the toxicities of Cr, Cd and Pb for microalga growth. The EC50 values of Cr for C. vulgaris were 0.22, 0.07 and 0.04 mg/L at 24, 48 and 72 h based on Algorithm 2 (%Ir, percent inhibition in average specific growth rate), respectively. The EC50 values of Cd for C. vulgaris were 2.76, 1.08 and 0.93 mg/L at 24, 48 and 72 h based on Algorithm 2, respectively. The EC50 values of Pb for C. vulgaris were 73.21, 65.02 and 48.38 mg/L at 24, 48 and 72 h based on Algorithm 2, respectively. The results laid a good foundation for the application of C. vulgaris in the water quality monitoring.

Improved feeding strategy to optimize growth and biomass for up-scaling rainbow trout Oncorhynchus mykiss (Walbaum 1792) farming in Himalayan region

Feeding is a key factor in the growth performance of rainbow trout farming, its sustainable production and profitability. However, supplying the daily ration in trout farming in flow-through system without any control is an inconceivable practice both economically and environmentally. In this study, the effect of different feeding regimes has been evaluated to optimize growth performance minimizing the feed wastage for simulating realistic intensive culture conditions (daily ration and feeding frequency per day depending on temperature and stocking density). Growth patterns of the reared fish in terms of average daily gain (ADG) and specific growth rate (SGR%) at two feeding schedules (FS-I & FS-II) and three stocking densities (Sd1, Sd2, Sd3) showed that the best performance was at Sd2 (R2 = 0.869) at FS-I and it was highly significant (P < 0.01). Regression coefficients (R2) of length-weight relationship in different seasons and stocking densities explained proper fit of the growth as per condition factor (K) and it was high (0.994 and 0.886) during monsoon and autumn respectively in FS-I showing more than 56% variability. Based on profitability analysis, and feed consumption efficiency (FCE) related growth performance, the size and temperature dependent feeding rate was determined to construe a new rate of feeding during different months of the year. The economic implications of the experimental feeding regimes were also assessed. Both the feeding regime FS-I & FS-II supported the extent of growth performance however, better performance in terms of ADG and SGR was observed in FS-I as compared to FS-II at the end of the trial. The results demonstrated a lower competition for feed since instant feed availability was higher at Sd2 and reared at FS-I. It is concluded that controlling the feeding process is essential to reduce wastage and increase profitability, which has been achieved by the monitoring process of environmental indicators and suitable feed management. Our findings suggest a new improved feeding schedule which has significant effects on feed intake and growth performance of rainbow trout besides containing the impacts of environmental indicators and eliciting cost-effective productions.

Exposure to Atrazine Impairs Behaviour and Growth Performance in African Catfish, Clarias gariepinus (Burchell, 1822) Juveniles

Clarias gariepinus juveniles of average weight, 17.57±1.95 g and an average length of 14.26±0.39 cm were exposed to environmentally relevant concentrations of 0 (control), 2.5, 25, 250, and 500 µg L-1 atrazine in a quality-controlled 28-day bioassay. Growth performance was assessed bi-weekly and fish samples were taken from different tanks to determine the relative growth rate, specific growth rate, feed conversion ratio, condition factor and behaviour. At the end of two weeks of exposure, the relative growth rate and the specific growth rate among exposed fish groups was found to reduce significantly (p&lt;0.05) compared to the control, an indication of poor growth performance. The average specific growth rates (SGR) of control fish is 3.86±0.02 %/w at the end of the exposure duration while recording -0.64±0.09 in the 500 µg L-1 group. Feed conversion ratio increased significantly from control to the group with highest atrazine concentration. Condition factor (K) of fish among treatment groups showed significant decrease in values with increasing concentration of atrazine in a dose-dependent pattern. Atrazine exposure resulted in behavioural anomalies including erratic swimming, clinging to the water surface, loss of equilibrium, lethargy, and discolouration. The behavioural responses were found to be concentration-dependent. The length-weight relationships for both control and atrazine exposed fish exhibited positive allometric growth and significant relationships as depicted by the value of R2 (coefficient of determination) except in the fish group exposed to 500 µg L-1 atrazine which exhibited negative allometric growth. Findings from this study indicate interference with normal behaviour and growth performance of C. gariepinus juveniles with ecological implications in water bodies exposed to atrazine even at reduced concentrations.

Effect of different dietary protein level on growth, production and survivability of threatened Mystus cavasius (Hamilton-Buchanan 1822) in pond habitat

A study was undertaken to determine the effect of different dietary protein levels on growth, survival and production of Mystus cavasius (Hamilton-Buchanan 1822) with three experimental diets containing 29%, 32% and 35% protein level applied simultaneously to three treatments T1, T2 and T3 respectively each with three replications. The stocking density (1, 11, 150/ha), initial weight (3.00±00 g) and length (2.00±0.00 cm) of fish were same for all the treatments. No significant (P&gt;0.05) difference was found for the mean values of water quality parameters. A suitable range of water quality parameters were recorded with the environment of experimental ponds. In terms of growth, production and survival, relatively highest performance was found in the treatment T3. After 180 days of rearing, average weight gain was 29.16±0.43 g, 31.17±0.30 g and 37.44±0.32 g with the above three different feeds, respectively. The average daily gain (ADG) and specific growth rate (SGR) of all treatments showed significant difference (P&lt;0.05) and the highest value (0.21±0.04 and 1.43±0.01%) was found with the 35% dietary protein level containing diet. Feed conversion ratio (FCR) improved with increase of dietary protein. The findings of FCR were 2.97±0.02 at 29% protein level (T1), 2.64±0.02 at 32% protein level (T2) and 2.20±0.01 at 35% protein level (T3). The results of protein efficiency ratio (PER) values were fairly similar of 1.17±0.02 and 1.18±0.01 for 29% and 32% protein level containing diets respectively indicating low efficiency and the highest efficiency (1.30±0.01) was found with 35% protein level. The findings of condition factor in different treatments for Mystus cavasius were not significantly (P&gt;0.05) varied with the treatments. Calculated values of condition factor were 1.04±0.00, 1.03±0.03 and 1.09±0.05 in treatment T1, T2 and treatment T3, respectively. In pond culture, the performance of treatment T3 was found to be better than the treatment T1 and T2. The production was of 3616±16.74 kg/ha in T3 during the culture period of six months. The best cost benefit ratio (CBR) value (1.98±0.02) was also found with treatment T3. The 35% dietary protein level with treatment T3 resulted in best growth performance and was probably adequate to meet the dietary protein needs of Mystus cavasius (Hamilton-Buchanan, 1822).&#x0D; Asian J. Med. Biol. Res. December 2020, 6(4): 659-673

Indirect assessment of internal irradiation from tritium decay on Lemna Minor duckweed

The response changes of the specific growth rate of Lemna minor duckweed was modeled using the logarithms of frond numbers on tritium activity concentration and gamma radiation dose from cobalt 60. The concept of average specific growth rate depends on the general exponential growth pattern, where toxicity is estimated based on the effect on the growth rate. One of the main questions of the effect of the radiation dose on duckweed is how to correlate the effect of beta radiation with the effect of any other radiation for modeling radiation on Lemna minor. Experimental data were extrapolated by utilizing the OECD guidelines.A linear relationship of absorbed dose and activity concentration was obtained for the average dependency growth rate of Lemna minor as D = (0.1257) · A0.585. The dose rate of gamma irradiation from 60Co increases with tritium activity dependence, on the specific growth rate of the Lemna minor duckweed. An increase in the tritium activity causes a decrease in the specific growth rate of the Lemna minor duckweed. It indicates that as the quantity of the beta radiation dose increase in Lemna minor duckweed, a higher quantity of gamma radiation will be required to cause the same effect in the specific growth rate of Lemna minor duckweed. The relation between the inhibition of the Lemna minor seedling growth and gamma and beta radiation dosage agrees roughly with that between the decrease of survival rate or fertility and dosage.

Assessment of growth characteristics, the survival rate and body composition of Asian sea bass Lates calcarifer (Bloch, 1790) under different feeding rates in closed aquaculture system.

One of the essential factors to be addressed in the development of aquaculture is the feeding regime. This study was investigated to assess the effects of feeding rate on growth performance, feed utilization, chemical body composition survival rate, cannibalism and morphological indices of Asian Seabass, Lates calcarifer. Intended for the trial, one hundred forty sea bass individuals with an average weight 5.47 ± 0.11 g were randomly distributed in 4 concrete tanks (914 cm × 183 cm 122 cm) each; length × width × depth) and volume 18,399 L, for total 68 days. The fishes were fed with a pelleted diet containing 46% crude protein for different feeding groups designated as (T1, T2, T3 and T4). The feed was supplied with a rate of (T1) 3%, (T2) 4%, (T3) 6%, and (T4) 9% of fish biomass per day and feeding frequency were maintained three times per day to all the groups. At the end of the trial water physicochemical parameters was in acceptable range for Asian sea bass growth. The average daily weight gain (g), weight gain (g) and specific growth rate (%) was significantly higher (p < 0.05) in T3 and T4 as compared to T1 and T2 group. The poorest feed conversion ratio was recorded in T1 group with 3% biomass per day. The cannibalism rate was significantly (p < 0.05) higher in T1 (3%) compared to T3 and T4 treatment. The morphological indices, condition factors (CF), viscerosomatic index and hepatosomatic index (HSI) was significantly higher in T4 group as compared to other treatments. The protein, moisture and ash contents of the whole biomass of the Asian sea bass were not significantly influenced by feeding rate. The fat levels in the fish bodies increased significantly (p < 0.05) with increasing feeding ratio. The phenomenal regression indicates that 6.5% feeding rate per day is optimum for best growth performance, survival and minimum cannibalism rate for Asian sea bass in captivity. The outcome of the finding will help in promotion for not only the coastal aquaculture in Pakistan abut also elsewhere.

Assessment of Immunostimulatory Characteristics of Achyranthes aspera Seeds and Leaves Supplemented Diets in Labeo rohita Fingerlings

The effect of dietary supplementation of leaves and seeds of Achyranthes aspera on rohu, Labeo rohita fingerlings was evaluated. Three experimental diets containing 0.25 (D1) and 0.5% (D2) leaves and 0.5% (D3) seeds of A. aspera and control diet (D4) without plant ingredients were formulated. After 45 days of feeding, rohu were immunized with 20% chicken RBC. Tissue and blood samples were collected on days7, 14 and 21 after immunization. Dietary supplementation significantly (P&lt;0.05) increased the average weight and specific growth rate of rohu. Serum lysozyme, myeloperoxidase, hemagglutination titer and nitric oxide synthase activities were significantly (P&lt;0.05) higher in D3 compared to others. This group was followed by D2 and D1. Significantly (P&lt;0.05) lower lipid and protein oxidations were found in D3 compared to others. This group was followed by D2 and D1. In hepatopancreas, lysozyme C, lysozyme G, tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) expressions were up-regulated while interleukin-10 (IL-10) expression was downregulated. In anterior kidney, lysozyme C, lysozyme G and IL-10 expressions were upregulated while TNF-α and IL-1β expressions were down-regulated. The dietary inclusion of leaves and seeds of A. aspera enhanced the growth, improved immune system and reduced oxidative stress of rohu.

Change in the state of an exploited fish population: From individual indicators to integral assessment

We adapted the approach used for the integral assessment of the status of ecosystems in order to assess population status. Classic theoretical concepts of fish population dynamics are the basis of this approach. The convolution of information about changes in several structural and functional characteristics into one integral index was performed using the analytical function of desirability. The index varied 0 to 1 and quantitatively characterizes the state of the population. This approach was tested on the example of the European grayling Thymallus thymallus (Linnaeus, 1758), inhabiting the Vym River (basin of the Northern Dvina River, North of the European part of Russia). The materials were collected during the environmental monitoring carried out by the Institute of Biology of Komi Science Centre of the Ural Branch of the Russian Academy of Sciences (IB FRC Komi SC UB RAS) in 2002, 2005–2019. The population parameters used in the calculations (relative abundance; average and maximum age of fish; the proportion of matured individuals in the 4+ age group; average specific growth rate of fish at the age of 6+; body weight of fish in the age group 6+) were characterized on the basis of the control net catches. Compared with the period 2005–2006, the value of the integral index in 2015–2018 decreased by almost two times. This indicates deterioration in the condition of the grayling group in the study area. There were no serious disturbances in the fish habitat in this area. The main hydrochemical and hydrobiological indicators have not changed significantly. The main reason for the observed changes is likely the significant increase in the impact of recreational anglers. The proposed integral index may be useful both for assessing the state of fish populations and for developing measures for the rational management of fish stocks.

Effects of dietary κ-carrageenan on growth and resistance to acute salinity stress in the black tiger shrimp Penaeus monodon post larvae

Acute salinity stress happens unnoticed in shrimp ponds and there is a need to protect the animals by providing dietary functional ingredients that will elicit resistance to this stress. k-Carrageenan, a sulfated polysaccharide from red seaweed, is reported to trigger innate immunity in vitro and in vivo in shrimps. The present study aims to evaluate its potential as growth-promoter and its immune-enhancement effects against salinity stress. Three separate experiments were done: (a) an attractability test; (b) a 30-day feeding trial to determine optimal inclusion of k-carrageenan, and (3) acute salinity stress test. Results of the attractability tests showed that all the experimental diets did not differ in their attractability to the shrimps. In the feeding trial, 5 groups of post larval shrimp were fed with 5 experimental diets containing various inclusion levels of k-carrageenan, namely, 0.0, 0.15, 0.30, 0.45, and 0.60 g kg-1. Results showed that the final average body weight (FABW), weight gain (WG), and specific growth rate (SGR) and feed conversion efficiency (FCE) values of shrimps in the 0.15 and 0.3 g kg-1 were significantly higher than that of the control group; the values of those in 0.45 and 0.60 g kg-1 groups were not significantly different from those of the control group. Protein efficiency ratio (PER) values, in contrast, were not significantly different from each group. Optimal inclusion level in the diet of k-carrageenan was 0.29 g kg-1. In the acute salinity stress test, 5 groups of shrimps were fed with the same 5 experimental diets as those in the feeding experiment for 2 weeks, transferred them from 21 ppt salinity media to 4 ppt. Results showed that the control group exhibited significantly highest mortality rate while in the 0.6 g kg-1 group the lowest; each group were significantly different from each other. Mortality rate decreased with increased dietary k-carrageenan level in a linear fashion. In conclusion, the study demonstrated that the the diets containing dietary k-carrageenan was equally as attractive as the basal/control diet and that k-carrageenan showed both growth-promoting and immune-stimulating effects against acute salinity stress in the black tiger shrimp P. monodon post larvae.

Monthly variation of growth, biochemical composition, fatty and amino acids patterns of gilthead sea bream (Sparus aurata) in offshore cage systems under brackish water conditions in the Black Sea

The aim of this study was to investigate seasonal variations of growth performance and biochemical composition, fatty and amino acids profiles of cage-cultured gilthead sea bream (Sparus aurata) in the Black Sea. The research was carried out on a yearly basis in the offshore cage systems of a commercial fish farm located on the coast of Samsun province, Turkey. Fish with an initial average weight of 2.44 ± 0.03 g reached a harvest weight of 474.60 ± 8.64 g with a survival rate of 94.26 ± 0.60% in 14 months. The average specific growth rate and feed conversion rate were 0.92 ± 0.30% and 1.45 ± 0.05 respectively. Seasonal variation of total essential and total non-essential amino acids and EAA/NEAA ratios ranged between 7.80 ± 0.00–11.22 ± 0.02 g/100 g, 8.19 ± 0.00–9.94 ± 0.01 g/100 g and 1.01 ± 0.00–1.18 ± 0.01 respectively (p < 0.05). The average of total ɷ-3, ɷ-6 and ɷ-9 values were 11.63 ± 0.68%, 24.29 ± 0.84% and 28.78 ± 0.17% respectively. It was determined that gilthead sea bream showed a remarkable growth performance over the 14 months period under offshore marine conditions in the Black Sea. Growth performance, biochemical composition, fatty and amino acids profiles in fish were influenced by seasonal changes of water temperature and nutritional value of the used diets. Findings of the present study provide remarkable information in terms of the year-round growth performance and meat quality of cage-cultured gilthead seabream based on a long-term evaluation throughout the full-cycle of 14-month production period of a commercial cage farm operating in offshore conditions in the Black Sea area.

Benfotiamine counteracts the negative effects of a high dietary carbohydrate on growth and ammonia toxicity resistance in post larval Penaeus monodon

The present study aimed to evaluate the effects of high carbohydrate diet in the absence of presence of dietary benfotiamine on growth and immune response against ammonia toxicity (50 mg NH4Cl L-1, average ambient temperature=27oC, pH 8.3) of post larval Penaeus monodon. A feeding trial involving three dietary treatments followed by an ammonia toxicity tests and a feed attractability test were conducted separately. During the feeding trial, shrimps were fed three experimental diets, namely, (1) a diet containing 15% starch (C), (2) a diet with 25% corn starch (high carbohydrate diet, HC) and (3) a diet containing both 25% starch supplemented with 0.2 g kg-1 benfotiamine (HCB). At the termination of the feeding trial, the shrimps were subjected to ammonia toxicity test to determine the effects of the diets on the immune response of the post larval shrimps. Attractability tests using customized aquaria showed that the HCB diet elicited significantly the highest attractability even after 10 min of feed placement in the feeding chamber. In the feeding trial that lasted for 60 days, results showed that shrimps fed with diet containing HCB exhibited significantly the highest growth rate (p&lt;0.05) among all groups of shrimps in terms of final average body weight (FABW), weight gain (WG), and specific growth rate (SGR); they also exhibited significantly the highest feed intake (p&lt;0.05). Upon challenge of the shrimps with 50 mg L-1 ammonia, shrimps fed with the HCB diet exhibited significantly the highest cumulative survival rate of 60% after 72 h while those fed with diet C and HC exhibited lower survival rates of 33% and 40%, respectively, and were not significantly different from each other. In conclusion, benfotiamine enhances attractability of the feed, growth performance and immune response against ammonia toxicity at the level of 0.2 g kg-1.

Dietary seaweed (Enteromorpha) polysaccharides improves growth performance involved in regulation of immune responses, intestinal morphology and microbial community in banana shrimp Fenneropenaeus merguiensis

The present study was conducted to evaluate the effects of marine polysaccharides from seaweed Enteromorpha on growth performance, immune responses, intestinal morphology and microbial community in the banana shrimp Fenneropenaeus merguiensis. Two thousand and four hundred juvenile shrimps with an average body weight of 2.18 ± 0.06 g were fed for 42 d with diets containing different levels of Enteromorpha polysaccharides (EPS): 0 (control), 1, 2 and 3 g/kg as treatment groups, each of group was replicated three times with two hundred shrimps per replicate. Dietary supplementation of 1 g/kg EPS showed a consistent improvement in the final weight, weight gain, average daily gain rate (ADGR) and specific growth rate (SGR) (P < 0.05), while showed a decrease in the feed conversion ratio (FCR) of shrimp (P < 0.05). Besides, the total anti-oxidative capacity (T-AOC), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione S-transferase (GST), lysozyme (Lyz), alkaline phosphatase (ALP), and phenoloxidase (PO) activities in hemolymph were enhanced by dietary supplementation of 1 g/kg EPS (P < 0.05), while it reduced the hemolymph MDA content (P < 0.05). Shrimp fed 1 g/kg EPS supplemented diets up-regulated FmLyz, FmSOD5 and FmCLAP gene expression level of hepatopancreas and gill (P < 0.05), and also improved the intestinal FmLC2, FmLyz, FmSOD5 and FmCLAP gene expression levels (P < 0.05). In addition, shrimp fed diets containing 1 g/kg EPS increased the villus width (P < 0.05) and resulted in a higher villus surface area (P < 0.05). According to 16S rRNA sequencing results, dietary supplementation of 1 g/kg EPS tended to increase the relative abundance of Firmicutes at phylum level (P = 0.07) and decrease the relative abundance of Vibrio at genus level (P = 0.08). There was a significant positive correlation between the relative abundance of Firmicutes and mRNA expression of intestinal immune-related genes (P < 0.05). These findings revealed that dietary 1 g/kg EPS could improve growth performance, enhance nonspecific immunity and modulate intestinal function of banana shrimp F. merguiensis.

Evaluation of the Cost of Production of Fish Clarias gariepinus Burchell, 1822 (Siluriformes, Clariidae) with Three Types of Food Based on Local Agricultural by-products in the Democratic Republic of Congo

Clarias gariepinus Burchell, 1822 is a catfish with high commercial value in the Democratic Republic of Congo and in several African countries. The breeding of this species is controlled, but Congolese fish farmers are confronted with the problem of a lack of compound feed in the form of granules. The recovery of local agricultural waste would be essential to fill this gap. The objective of this study is to evaluate the effect of three types of food based on local agricultural by-products on the growth of C. gariepinus. The 25%, 41% and 51% crude protein feed formulas were tested in duplicate for 96 days. Fry averaging 2.20±0.43 g were distributed in 6 closed-loop plastic containers. The fish were fed twice a day by hand. Weighing and measuring took place every 14 days. The results obtained show that the highest final average weight (g) and specific growth rate (%/d) (F = 2.87; p = 0.002) are obtained with food A1: 27.5±1.9 g and 0.25±0.15% /d respectively. It took 812.6 Congolese francs to develop food A1, 942.6 congolese francs to produce the A2 ration and 836.6 congolese francs to produce food A3. The A1 ration is the one that gave a better compromise in price and quality by promoting fish growth at a lower cost (3.827 congolese francs).

Feeding frequency influences the growth performance of yellowfin seabream (Acanthopagrus arabicus) in cage culture

This study examined the growth response of yellowfin seabream, Acanthopagrus arabicus, reared in floating net cage fed at variable daily frequencies. Thirty healthy fish (49.7±0.3 g initial weight) were stocked in 12 separate net cages (1.5x 1.5 x 1.5m) assigned to four different frequency groups, two, three, four and six times/day designated as FF1, FF2, FF3 and FF4, respectively. Four semi-purified diets 42% protein level and were used to feed at seven percent body weight (%BW) per day for a total period of forty five days. The fish length and weight data were taken fortnightly and the feeding was adjusted according to the new weight. The fishes remained healthy and active during the whole experimental period, 95-100% survival rate was recorded. At the end of the feeding trial final weight, average daily weight gain (ADG) and specific growth rate (SGR) values were significantly higher for fish in groups FF3 and FF4 compared to FF1 and FF2. The SGR was high at six times/day (FF4, 1.3±0.04) and four times/day frequency (FF3, 1.3±0.02) with no significant difference, however, a significant reduction in growth was recorded at two times/day (FF1, 1.09±0.01) and three times/day (FF2, 0.99±0.02) frequency. There were no significant differences in fish whole body proximate composition (protein, ash, moisture and lipid) of fish fed in all groups. It may be concluded from the present study that yellowfin seabream, A.arabicus, was assessed for the first time and that it may be grown in floating cages effectively by feeding four times/day which would yield significantly better results under given rearing conditions.

Complete replacement of fishmeal by soybean and poultry meals in Pacific whiteleg shrimp feeds: Growth and tolerance to EMS/AHPND and WSSV challenge

Corresponding to projected global population growth, the world's food production systems must likewise enlarge substantially if current levels of dietary protein intake are to be maintained. The anticipated growth curve for global aquaculture, and especially for shrimp farming, which is forecast to double production by 2030, will inevitably result in shortfalls in currently favored dietary ingredients: fishmeal (FM) and fish oil (FO). Servicing the projected FM-FO shortfall with marine products would be a formidable task as economic, social, moral, safety and environmental issues have forced the feed sector to examine the use of alternative, non-marine, ingredients. Herein, various alternative protein and lipid sources were evaluated as substitutes for FM-FO in Pacific whiteleg shrimp diets. Growth trials were coupled to challenges with viral and bacterial pathogens to assess potential benefit or disadvantage of ingredient switching. No differences (P > .05) were observed between control and test diets regarding growth or survival, Average Daily Gain (g d−1) or Specific Growth Rate (% d−1) over a 56-day period. Moreover, response to post-feeding trial challenge with EMS/AHPND or WSSV also did not differ between diets (P > .05). However, there was a difference in size/age responsiveness to bacterial challenge, with younger animals succumbing to infection more rapidly (P ≤ .035). Similar responses were observed for shrimp exposed to WSSV over the first 5-days post-challenge (P ≤ .02) after which survival rates equalized. Overall, the results support the sustained belief that FM-FO constituents of Pacific whiteleg shrimp diets can be totally replaced by non-marine ingredients that are nutritionally equivalent. Improvement in responsiveness to substitute proteins and oils might be further gained with more judicious blending of ingredients and use of other additives. Such manipulations could also result in less expensive sustainable feeds.

Effectiveness of Heat Shock (40°C) With Different Duration for Tetraploid Formed in Mutiara Catfish (Clarias sp.) Juvenile

This study seeks to determine the best method for preventing separating one cell into two cells in early embryogenesis as a means to induce tetraploid in the Mutiara catfish strain (Clarias sp.). Heat shocks were applied to newly fertilized eggs. Heat shock that was administered at 40 °C, for 4 min at 30 min post-spawning, was the best method for tetraploid induction, as evidenced by the highest percentage of forming four pronuclei in syngamy (84.12%). Therefore, heat shock induction was employed to further explore the advantage of tetraploid over diploid catfish. After hatching of the heat-shocked eggs, the larvae were allowed to reach juvenile levels of development. At day 30 in culture, the number and amount of chromosomes were determined in juvenile stages, using Silver Nitrate Staining methods, by which the catfish were divided into diploid and tetraploid groups. The average specific growth rate of the tetraploid (22.55%/gr/day) was significantly higher (Pb 0.05) than that of their diploid counterparts (15.42%/gr/day). These results reveal the advantages of growing tetraploid over diploid Mutiara catfish strain and its feasibility for future commercial production.

Effect of light intensity on survival, growth and physiology of rohu, Labeo rohita (Cyprinidae) fry

Purpose: Light intensity is one of the important environmental factors that have strong influence on larviculture. Culture of fish at high intensity of light generates harmful radicals in the body that can compromise their health and production. The present study aims to evaluate the effect of various light intensities on the physiology of rohu Labeo rohita fry.Materials and Methods: Rohu fry (13.56 ± 0.4 mg) were exposed at five different light intensities: 0.17 ± 0.005 (Lc, control), 1.45 ± 0.23 (L1), 2.69 ± 0.47 (L2), 3.93 ± 0.72 (L3) and 5.06 ± 0.95 Wm−2 (L4). After 90 days of culture, rohu were harvested.Results and Conclusions: A 2-5% mortality of rohu was recorded in L3 and L4 treatments. The average weight and specific growth rate were significantly (p < .05) higher in Lc treatment compared to others. The light intensity and swimming activity of rohu showed direct relationship, whereas, light intensity showed inverse relation with nitric oxide synthase and reduced glutathione levels. Significantly (p < .05) higher glutathione S-transferase and glutathione peroxidase activies were found in rohu exposed at L4 treatment. Higher light intensities resulted in oxidative stress in the muscles of rohu. Thiobarbituric acid reactive substances, carbonyl protein and heat shock protein 70 were significantly (p < .05) higher in rohu exposed at L4 compared to other treatments. Exposure of rohu fry to intense light resulted into physiological stress and immunosupression.

Benfotiamine counteracts the negative effects of a high dietary carbohydrate on growth and ammonia toxicity resistance in post larval Penaeus monodon

The present study aimed to evaluate the effects of high carbohydrate diet in the absence of presence of dietary benfotiamine on growth and immune response against ammonia toxicity (50 mg NH4Cl L-1, average ambient temperature=27oC, pH 8.3) of post larval Penaeus monodon. A feeding trial involving three dietary treatments followed by an ammonia toxicity tests and a feed attractability test were conducted separately. During the feeding trial, shrimps were fed three experimental diets, namely, (1) a diet containing 15% starch (C), (2) a diet with 25% corn starch (high carbohydrate diet, HC) and (3) a diet containing both 25% starch supplemented with 0.2 g kg-1 benfotiamine (HCB). At the termination of the feeding trial, the shrimps were subjected to ammonia toxicity test to determine the effects of the diets on the immune response of the post larval shrimps. Attractability tests using customized aquaria showed that the HCB diet elicited significantly the highest attractability even after 10 min of feed placement in the feeding chamber. In the feeding trial that lasted for 60 days, results showed that shrimps fed with diet containing HCB exhibited significantly the highest growth rate (p&lt;0.05) among all groups of shrimps in terms of final average body weight (FABW), weight gain (WG), and specific growth rate (SGR); they also exhibited significantly the highest feed intake (p&lt;0.05). Upon challenge of the shrimps with 50 mg L-1 ammonia, shrimps fed with the HCB diet exhibited significantly the highest cumulative survival rate of 60% after 72 h while those fed with diet C and HC exhibited lower survival rates of 33% and 40%, respectively, and were not significantly different from each other. In conclusion, benfotiamine enhances attractability of the feed, growth performance and immune response against ammonia toxicity at the level of 0.2 g kg-1.

Comparative study on phenoloxidase activity of biofloc-reared pacific white shrimp Penaeus vannamei and Indian white shrimp Penaeus indicus on graded protein diet

Shrimp aquaculture demands technological advancement that boosts production and environmental sustainability. This study evaluated and compared the growth performance and innate immunity of two species of shrimp (Pacific White shrimp Penaeus vannamei and India white shrimp Penaeus indicus) reared under biofloc technology with different dietary protein levels (Low-25%, Medium-30% and High-35%). As prophenoloxidase (proPO) activity is an important parameter in immune response of shrimp, we focused on the dynamics of prophenoloxidase induced by three different activators (Sodium dodecyle sulfate, (SDS, Trypsin & Laminarin). At the end of the experiment, the effect of activators on proPO activity in serum, plasma and hemocyte lysate (HLS) was evaluated in both the species under conventional and biofloc systems with graded proteins. This experiment lasted for a month as nursery rearing followed by 60 days of grow-out culture. There was no significant difference (p < 0.05) in growth performances of both the species reared under biofloc, whereas control group exhibited lower growth. Significantly higher average body weight (ABW), survival and specific growth rate (SGR) were observed in medium protein groups reared under biofloc than the other biofloc groups and control. The medium protein groups also showed significantly lower (p < 0.01) TAN, NO2–N, and NO3–N levels compared to other treatments and the control exhibited considerably higher TAN, NO2–N and NO3–N levels. The proPO activity in serum of both the shrimps were found to be significantly higher (p < 0.05) than the control in which highest proPO activity was observed in SDS activated groups irrespective of the graded protein levels. A similar trend was observed in the plasma of P. indicus in which SDS activated group fed with high protein level showed highest proPO activity, whereas in plasma of P. vannamei trypsin activated groups fed with low protein level showed higher proPO activity than SDS and laminarin activated groups. The HLS of P. vannamei showed highest proPO functioning in trypsin activated group fed with high protein level, whereas in P. indicus, the highest proPO activity was observed in SDS activated group fed with high protein diet. Though in many cases, the groups fed with high protein diet showed highest proPO activity, the low protein and the medium protein groups also exhibited upregulation in the immune response parameter reared under biofloc irrespective of the species. SOD activity of the hemocytes were influenced by different dietary protein levels and better inhibition was observed in HP when compared to control and other treated groups. Thus the native non-SPF Indian white shrimp P. indicus has comparable potential as the SPF Pacific white shrimp P. vannamei in terms of innate immunity, immune response, and growth when reared under biofloc conditions.