Satiation Level Research Articles

Optimization of dietary protein based on ideal protein concept for genetically improved farmed tilapia (GIFT) juveniles reared in inland saline water

A 60-day feeding trial was performed to optimize dietary protein based on the ideal protein concept for genetically improved farmed tilapia (GIFT) juveniles reared in inland saline water (ISW) of 10 ppt salinity. Seven heteronitrogenous (373.6–256.5 g crude protein/kg), isocaloric (∼ 16 MJ digestible energy/kg) and isolipidic (∼ 80 g lipid/kg) semi-purified feeds were formulated and prepared with decreasing levels of crude protein (CP), namely 373.6 (CP1), 352.2 (CP2), 334.5 (CP3), 314.9 (CP4), 293.7 (CP5), 275.2 (CP6) and 256.5 g/kg (CP7). The proportion of total essential and semi-essential amino acids was kept constant in all diets as ideal amino acid profiles and total non-essential amino acids were reduced linearly to reduce the dietary CP levels. Three hundred fifteen juveniles (average weight 4.76 ± 0.01 g) were randomly assigned into seven groups in triplicate. Fish of various groups were fed thrice daily at an apparent satiation level. The growth of juveniles increased linearly and quadratically (p<0.05) when the CP level of diets was decreased from 373.6 (CP1) to 334.5 g/kg (CP3), then declined linearly. The CP2 and CP3 groups had significantly higher feed intake and lower feed conversion ratio. In contrast, low CP-fed groups had superior protein utilization, viscerosomatic index and hepatosomatic index than other groups. The CP1 and CP2 groups had significantly higher whole-body protein and lower lipid content. The whole-body non-essential amino acid content diminished linearly (p<0.05) as dietary CP levels were decreased; the whole-body essential amino acid content remained unchanged (p>0.05). The high CP-fed juveniles (CP1 and CP2) showed a significantly (p<0.05) elevated protease activity, whereas the opposite trend was noticed for amylase activity. The aminotransferase activities of the liver and muscle were reduced linearly (p<0.05) with reduced dietary CP levels. Serum glucose and cholesterol contents elevated linearly (p<0.05) with decreased dietary CP levels. Whereas, the hemoglobin content and RBC count decreased (p<0.05) in the high CP-fed juveniles. The second-order polynomial regression analysis revealed that the optimal dietary CP levels could range from 311.1 to 318.0 g/kg for GIFT juveniles reared in ISW of 10 ppt salinity. Furthermore, by adopting the ideal protein concept, the CP levels in the diet of GIFT juveniles could be reduced from 373.6 to 311.1 g/kg without affecting growth performance. The outcome of this study will assist in developing a low-protein feed with balanced essential amino acids for GIFT culture in ISW.

Efeito da inclusão de Ceratophyllum demersum cru e fermentado na dieta sobre o desempenho de crescimento e digestibilidade em juvenis de carpa capim, Cte-nopharyngodon Idella Val.

A 12-week feeding experiment was conducted to evaluate the growth performance, feed efficiency, digestibility and carcass composition of young grass carp Ctenopharyngodon idella (Val, 1844) (4.03±0.16 g) fed on a control diet and two experimental diets (38.5% crude protein). The experiment aimed to assess the utilization of raw hornwort Ceratophyllum demersum (HR) and fermented (HF) by adding 20% of each of the alternative ingredients separately to the control diet (C) to completely compensate barley, a portion of wheat bran and 20% of fish meal. Results indicated that all growth and feed efficiency parameters among groups were no significantly different (P&gt;0.05) in specific growth rate (SGR), food conversion ratio (FCR), protein efficiency ratio (PER), and protein productive value (PPV) of fish fed HR and HF with the control diet. There was no effect (P&gt;0.05) in stimulating digestibility (ADCtotal) when HR and HF were added to the diet. Both HR and HF produced significantly (P&lt;0.05) higher satiation level associated with lower dietary digestible energy contents. The evacuation rate was not affected significantly (P&gt;0.05) by the inclusion of raw or fermented hornwort. Whereas, the moisture, protein and lipid levels in carcass were similar (P&gt;0.05) in all groups, except for the control diet (C), which recorded the highest ash level (P&lt;0.05). In conclusion, the incorporation of raw or fermented hornwort up to 20% level was found to be not suitable, and there were adverse effects on the growth and feed efficiency of experimental fish.

Effects of dietary Spirulina platensis on growth performance, body composition, haematology, immune response, and gut microflora of stinging catfish Heteropneustes fossilis

The study was conducted to determine the inclusion effect of Spirulina platensis as a feed supplement on growth performance, feed efficiency, body composition, haematology, immune response, and gut microflora of the stinging catfish (Heteropneustes fossilis). Five iso-nitrogenous and iso-lipidic diets were prepared by replacing fish meal (FM) with S. platensis at a rate of 0, 2.5, 5, 7.5, and 10% and referred to as control, SP2.5, SP5, SP7.5, and SP10 diets, respectively. Three replicate groups of fish (average weight of 0.75 g) were reared in glass aquaria (180 L water capacity) and fed with each of the experimental diets up to satiation level twice a day, 7 days a week for 70 days. At termination, growth performance, carcass composition, immune parameters, and gut microflora were assessed. Moreover, ten fish from each aquarium were challenged with Aeromonas hydrophila and cumulative mortality was recorded for 15 days. Significantly (P < 0.05) higher weight gain, specific growth rate (SGR, % day−1), lower feed conversion ratio (FCR), and higher protein efficiency ratio (PER) were recorded in fish fed with SP7.5 and SP10 diets compared to control. Dietary S. platensis inclusion at 7.5–10% levels significantly (P < 0.05) boosted the whole-body protein and ash contents of stinging catfish, while decreasing the lipid and moisture contents compared to the control. Haematological parameters significantly (P < 0.05) improved in the S. platensis supplemented diet compared to the control. Serum lysozyme activity of fish fed with SP7.5 and SP10 diet was significantly (P < 0.05) higher compared to all other diets. Higher inclusion of S. platensis lowered post-challenge mortality and the lowest cumulative mortality (30%) was recorded in fish fed with the SP7.5 diet compared to the control (70%). Pseudomonas, Lactobacillus, and Lentibacillus were the prevalent genera in the gut microbiota found in the metagenomics study and the abundances of the above microbiota gradually increased with the level of dietary S. platensis inclusion. Based on the findings of the study, 7.5–10% inclusion of S. platensis was the most recommendable in stinging catfish diet to improve growth performance, feed utilization, body composition, haematology, immunological response, and gut microbiology. However, based on the regression analysis the optimum inclusion level of S. platensis as a feed supplement was calculated to be 9.3–9.9% in stinging catfish.

Using the conditioned place preference paradigm to assess hunger in dairy calves: Preliminary results and methodological issues.

Dairy calves are typically fed restricted amounts of milk. Although feed restrictions are predicted to result in negative affective states, the relative aversiveness of 'hunger' remains largely unexplored in this species. Here, we investigated whether the conditioned place preference paradigm can be used to explore how calves feel when experiencing different levels of satiation. This paradigm provides insight into what animals remember from past experiences, the assumption being that individuals will prefer places associated with more pleasant or less unpleasant experiences. Sixteen Holstein calves were either fed a restricted (3L per meal totalling 6 L per day) or 'enhanced' milk allowance (ad libitum up to 6 L per meal totalling up to 12 L per day) in their home-pen. Calves were then placed in a conditioning pen for 4 h immediately after being fed their morning meal to allow them to develop an association between the pen and their state of post-prandial satiation. Calves were conditioned across four days with their satiation state alternating between days to allow them to develop an association between pen and satiation levels. On the 5th day, calves were individually allowed to roam freely between the two pens for 30 min. We expected that calves would prefer the pen where they previously experienced higher levels of satiation, but our results show no to limited effects of treatment. However, some methodological issues (colour and side bias) prevent us from drawing strong conclusions. We discuss reasons for these issues and potential solutions to avoid these in future studies.

Sugarcane bagasse biochar enhances the growth parameters, haematological parameters, and enzyme activities of genetically improved farmed tilapia (GIFT) reared in inland saline water.

In the present scenario, waste management, especially agro-waste, is one of the major challenges. India is an agrarian country and the economy depends on agriculture and a huge amount of agro-wastes are generated. In this study, biochar was prepared from paddy straw and sugarcane bagasse and was used in the feed of genetically improved farm tilapia (GIFT) at 0.5% (w/w) basis to study its effect on growth and haematological parameters. An experiment was carried out in triplicate in 500-l capacity FRP tanks comprising two treatments and one control. Tanks were filled with inland saline soil to maintain 25-cm soil's bed and water with 12 ppt salinity. A total of 22 fish having an average length of 5.14 ± 0.07cm and weight of 4.8 ± 0.05g were stocked in each tank; the fish were fed at apparent satiation level, twice daily for 45days. It was observed that growth parameters like SGR% (specific growth rate), weight gain (WG%), and feed conversion ratio (FCR) were significantly improved (p < 0.05) than the control. Biochar-enriched feed also significantly improved the haematological parameters like red blood cell (RBC), white blood cell (WBC), haemoglobin (Hb) haematocrit % (HCT), mean cell haemoglobin concentration (MCH), and MCV (mean cell volume) in treatment groups than the control. Feeding biochar as feed additives was also found to decrease catalase (CAT) and enhanced amylase and lipase activities in treatments as compared to control (p < 0.05). It can be concluded that the application of biochar as a feed additive enhanced the growth and overall health of the fish, and it can enhance fish production. However, biochar from sugarcane bagasse was found to be more effective than the paddy straw biochar in the diet of tilapia (GIFT).

Effect of Different Dietary Starch Inclusion Levels on Growth Performance, Glucose Metabolism, Histological Alterations and Modulation of Hepatic Gene Expressions in Genetically Improved Labeo rohita (Jayanti Rohu)

Background: Feed cost mainly constitutes 40-60% of total aquaculture production expenses, due to the inclusion of expensive animal-derived ingredients to the feed industry. Studies suggested that herbivore and omnivore fish species can consume higher level of carbohydrate (150–300 g/kg starch) as compared to carnivore fish. However, lower carbohydrate utilization in fishes is less understood till date. In the present work, It was attempted to decipher the physiological changes in genetically improved rohu (Jayanti Rohu) upon inclusion of different levels of starch in the feed regime. Methods: Three isonitrogenous (24% crude protein), isolipidic (10% ether extract) experimental diets viz. TS20 (@20% starch), TS30 (@30% starch) and TS40 (@40% starch) were formulated and fed to Jayanti Rohu fingerlings (180 number with average weight of 45±3.5 g) twice daily up to satiation level for 45 days experimental period. The growth performance, nutrient utilization, histological changes and modulation of hepatic gene expressions were evaluated after completion of experiment. Result: Results indicated significantly (p less than 0.05) increased weight gain percentage, SGR and condition factor in TS30 and TS40 as compared to TS20. The histoarchitecture of hepatic cells depicted greater cell damage with increasing levels of dietary carbohydrates. The glucose membrane transporter 2 gene and carbohydrate metabolism involved genes showed a higher expression in TS40 and TS30 compared to TS20. Therefore, the present study concluded that inclusion level of 30% starch as optimal level in the diet of genetically improved Jayanti rohu.

Effect of graded levels of dietary methionine on growth performance, carcass composition and physio-metabolic responses of genetically improved farmed tilapia (GIFT) juveniles reared in inland saline water of 10 ppt

The current study aimed to optimize dietary methionine level for improving growth performance, carcass composition and physio-metabolic responses of genetically improved farmed tilapia (GIFT) juveniles reared in inland saline water of 10 ppt. Seven isonitrogenous (∿370 g crude protein/kg), isolipidic (∿80 g lipid/kg) and isocaloric (∿19 MJ gross energy/kg) purified diets were made with graded levels of methionine viz., 4.9 (M4.9), 7.2 (M7.2), 9.9 (M9.9), 12.3 (M12.3), 15.1 (M15.1), 17.4 (M17.4) and 19.8 g/kg (M19.8) with a constant level of cystine (3.2 g/kg). Completely randomized designs were followed to constitute seven distinct experimental groups and each group comprised of three experimental units. Fifteen juveniles (3.16 ± 0.01 g) were randomly stocked in each experimental unit. During the 60-day feeding trial, juveniles were fed with their respective experimental diets thrice daily at an apparent satiation level. The results revealed that growth (weight gain percentage, thermal growth coefficient and specific growth rate) and feed and nutrient utilization (feed conversion ratio, protein efficiency ratio and apparent net protein retention) were improved significantly with an increment in dietary methionine levels up to 12.3 g/kg, and methionine supplementation beyond that did not give extra benefit in relation to growth performance. Dietary methionine supplementation at various levels had no effect (P > 0.05) on the body indices, survival, carcass moisture and ash content and carcass essential amino acid composition of GIFT juveniles. The carcass protein level increased with an increment in dietary methionine levels up to 12.3 g/kg and then declined with further increment of dietary methionine level. However, carcass lipid content displayed the inverse trend of carcass protein content. GIFT juveniles fed a diet containing 12.3 and 15.1 g methionine/kg displayed elevated activities of liver and muscle aminotransferases activities, while the activity of digestive enzymes was unchanged among dietary groups. An increment of methionine up to 12.3 g/kg of diet resulted in a significant rise in serum protein and globulin concentration. Based on broken-line linear and second-order polynomial regression analysis in relation to weight gain percentage and feed conversion ratio, the optimum methionine requirements for GIFT juveniles reared in inland saline water of 10 ppt ranged from 12.1 to 14.1 g/kg of diet (32.7–38.1 g/kg of dietary protein) with supplementation of cystine at 3.2 g/kg.

The Performances of Hybrid Grouper, Epinephelus fuscoguttatus × E. lanceolatus Fed with Defatted Soybean Meal-Based Feeds with Supplementation of Phytase

Fish meal is the primary protein ingredient in fish feed and this material is expensive and non-renewable. However, the use of plant protein in marine fish feed such as soybean meal products are limited due to anti-nutritional factor that hindered fish performances. Therefore, hybrid grouper, a cross between tiger grouper (Epinephelus fuscoguttatus) and giant grouper (E. lanceolatus) was evaluated using defatted soybean meal (DSM) based feed and phytase. DSM- based feeds (30% of protein replacement) with supplementation of phytase at 0 and 2000 FTU/kg dosages, as well as a control feed (CON) comprised completely of fish meal (FM) was given to the hybrid grouper with an initial body weight of 6.2±0.0g. Each experimental feed was formulated with 50% of crude protein and 12% of crude lipid. The fish were raised in 100L fiberglass tanks equipped with a flow-through water system for each triplicate treatment. The hybrid grouper was fed with the respective feeds twice a day until the perceived satiation level for 12 weeks. Hybrid grouper fed CON and DSM-based feed did not exhibit any significant difference in growth. However, hybrid grouper fed with DSM-based feed grew larger compared to that fed with CON. Hybrid grouper fed with DSM-based feed showed significantly higher feed intake, lower net protein utilization, hepatosomatic index, viscerosomatic index, and apparent digestibility coefficient (ADC) protein values (p&lt;0.05). The value of ADC of phosphorus was slightly higher in DSM-based feed supplemented with phytase at a dosage of 2000 FTU/kg. No significant effect was observed on body proximate composition, morphological condition of the intestine, and ADC of lipids in all the treatments. The results show that hybrid grouper can effectively consume 30% DSM-based feed and supplementing phytase did not affect the fish performances.

Growth and production performance of Mud Eel, Monopterus cuchia (Hamilton, 1822) using different types of feed in the Northern region of Bangladesh

The experiment was conducted to assess the growth and production performance of freshwater Mud Eel (Monopterus cuchia) using different types of feed in nine earthen ponds in Bogura and Naogaon district of Bangladesh over a period of 180 days from 01 July, 2020 to 31 December, 2021. Three different treatments having three replicates each [T1 {Live fish spawn (60%), Vermi compost (40%)}, T2 {Live fish spawn (40%), Fish paste (60%)} and T3 {Vermi compost (40%), fish paste (40%), Rice bran (10%) and Wheat flour (10%)}] were used where significantly higher (P&lt; 0.05) gross production and low FCR were recorded in T1 treatment. Juvenile cuchia were stocked @ 400 nos/dec in each treatment having mean initial body weight of 25 g and mean initial body length of 20 cm where highest weight gain of 130.09±1.79 g was found in T1 (p&lt;0.05), followed by the T2 (112.89±1.51 g) and T3 (95.02±0.16 g). Survival rate (82.11±2.21%) and specific growth rate (1.01± 0.02 % day-1) were also found to be highest in T1 compared to the T2 and T3. Feed were applied twice a day up to satiation level using feeding tray to check feeding performance of fish. Water quality parameters like temperature, dissolved oxygen, pH and alkalinity were in the optimum range for fish culture. Results from the present study clearly indicate that live fish spawn and vermi compost is suitable for the grow-out culture of M. cuchia in earthen ponds for its better growth, survival rate and production.

Effect of Dietary Lipid Level on Growth Performance, Body Composition, and Physiometabolic Responses of Genetically Improved Farmed Tilapia (GIFT) Juveniles Reared in Inland Ground Saline Water.

A 60-day feeding trial was carried out to determine the effect of dietary lipid levels on growth and physiometabolic responses to optimize the dietary lipid requirement for maximizing the growth of Genetically Improved FarmedTilapia (GIFT) juveniles reared in inland ground saline water (IGSW) of medium salinity (15 ppt). Formulation and preparation of seven heterocaloric (389.56-449.02 Kcal digestible energy/100 g), heterolipidic (40-160 g/kg), and isonitrogenous (410 g/kg crude protein) purified diets were done for conducting the feeding trial. Random distribution of 315 acclimatized fish (mean weight 1.90 ± 0.01 g) was made in seven experimental groups such as CL4 (40 g/kg lipid), CL6 (60 g/kg lipid), CL8 (80 g/kg lipid), CL10 (100 g/kg lipid), CL12 (120 g/kg lipid), CP14 (140 g/kg lipid), and CL16 (160 g/kg lipid) with 15 fish per triplicate tank (fish density, 0.21 kg/m3). Respective diets were used for feeding the fish at satiation level three times daily. Results indicated that weight gain percentage (WG%), specific growth rate (SGR), protein efficiency ratio, and protease activity significantly increased up to 100 g lipid/kg fed group, and then the values significantly decreased. Muscle ribonucleic acid (RNA) content and lipase activity were highest in 120 g/kg lipid-fed group. RNA/DNA (deoxyribonucleic acid) and serum high-density lipoproteins levels of 100 g/kg lipid-fed group were significantly higher than 140, and 160 g/kg lipid-fed groups. The lowest feed conversion ratio was found in the 100 g/kg lipid-fed group. The amylase activity was significantly higher in 40 and 60 g lipid/kg fed groups. The whole-body lipid level was increased with increasing the dietary lipid levels, whereas, there was no significant difference in whole-body moisture, crude protein, and crude ash contents of all groups. Highest serum glucose, total protein and albumin, and albumin to globulin ratio and lowest low-density lipoproteins level were found in 140 and 160 g/kg lipid-fed groups. Serum osmolality and osmoregulatory capacity did not vary significantly, whereas carnitine palmitoyltransferase-I and glucose-6-phosphate dehydrogenase showed an increased and decreased trend, respectively, with the increasing dietary lipid levels. According to second-order polynomial regression analysis based on WG% and SGR, the optimum dietary lipid for GIFT juveniles in IGSW of 15 ppt salinity was found to be 99.1 and 100.1 g/kg, respectively.

Pyrroloquinoline quinone supplemented diet enhances metabolism, feed intake and growth in common carp (Cyprinus carpio Linnaeus, 1758) reared at low temperature

A pilot study was conducted to delineate the potential of dietary pyrroloquinoline quinone (PQQ) on Cyprinus carpio Linnaeus, 1758, at water temperature of 12-14oC using a recirculatory system with water flow rate of 1.8 l min-1. Six isonitrogenous (32% CP) and iso-caloric (16.7 MJ kg-1) diets were prepared with varying levels of PQQ viz. control (0 mg kg-1), T1 (0.2 mg kg-1), T2 (0.4 mg kg-1), T3 (0.6 mg kg-1), T4 (0.8 mg kg-1) and T5 (1.0 mg kg-1). Two hundred and sixteen common carp juveniles were distributed randomly into control and five treatment groups in triplicates with 12 fish per tub and fed twice daily at satiation level for 30 days. Results indicated that dietary quinone at 0.8 mg kg-1 significantly increased the feed intake and weight gain, specific growth rate (SGR), feed conversion ratio (FCR) as well as protein efficiency ratio (PER) were significantly higher (p&lt;0.05) than non-quinone fed group. The thyroid hormone levels as well as digestive and metabolic enzyme activities were significantly higher (p&lt;0.05) in treatments than in control. The superoxide dismutase (SOD) activity in liver was significantly higher (p&lt;0.05) in T1, T2 and T5. Catalase activity in gill was significantly higher (p&lt;0.05) in control and lowest in T3 and T4. Therefore, quinone can be used as a feed additive for enhancing feed intake, enzymatic activities and growth during winter. Keywords: Feed additive, Feed intake, Metabolism, Pyrroloquinoline quinone, Winter feeding

Shrimp shell waste-derived astaxanthin in synergistic combination with its commercial variant augments gonadal maturation and upregulates vitellogenin gene expression of discus (Symphysodon aequifasciatus)

A study was performed to evaluate the efficacy of shrimp shell meal derived natural astaxanthin (SSM), supplemented with its commercial variant on gonadal maturation and vitellogenin gene (Vtg.) expression in reproductively active adults of the high-value ornamental cichlid discus (Symphysodon aequifasciatus) reared under captivity. Four isonitrogenous (50% crude protein), isolipidic (9% ether extract), and isocaloric (400 kcal digestible energy/100 g) experimental diets viz. control (commercial grade astaxanthin, without SSM), T1 (15% SSM + commercial astaxanthin), T2 (20% SSM + commercial astaxanthin), T3 (25% SSM + commercial astaxanthin) were prepared and fed to satiation level twice daily for the entire experimental period of 90 days. Results revealed significant (p < 0.05) linear, quadratic, and overall trends, wherein GSI increased with an increase in the proportion of SSM in the diet, with higher GSI recorded in T2 and T3 treatment groups (testis and ovary, respectively), which were significantly (p < 0.05) different from other groups. The overall linear and quadratic trends of HSI differed significantly (p < 0.05) with the variability in proportions of natural and commercial astaxanthin combinations and were found highest in the T2 treatment group. Cholesterol, FSH, LH, 11-KT, 17β- Estradiol, and 17α-20β DHP levels increased with an increasing proportion of natural astaxanthin and recorded the highest values in the treatment T2 with an overall significant linear and quadratic trend as compared to other treatments. Most of the oocytes of T2 and T3 groups were in the vitellogenic phase, i.e., primary, secondary, and tertiary yolk stages. More spermatids were visible in testicular tubules in T2, followed by T3 and T1. The abundance of Vtg. mRNA was significantly (p < 0.05) evident in T2, followed by T1, then in control. Further increase in SSM inclusion caused a downregulation in the expression of this gene in the T3 group. The dietary combination of SSM @200 g/kg diet with its synthetic/commercial variant exhibited optimum performance at combination levels of 77.5 and 22.5 mg/kg, respectively, evidenced in terms of changes in steroid hormone profiles, gonadal maturation and vitellogenin gene expression in comparison to the control, which contained the dietary synthetic/commercial variant of astaxanthin alone. These inferences are presumably a milestone in the captive broodstock development of this high-value ornamental cichlid, S. aequifasciatus, with an added advantage of cost-effectiveness. The study would help the utilisation of economically important bio-waste in combination with commercial variants for effective value addition in the ornamental fish feed industry.

Dietary lysine requirement of juvenile Pacific white shrimp, Litopenaeus vannamei (Boone, 1931) reared in inland saline water of 10 ppt salinity

A feeding trial of 60 days was conducted to assess the dietary lysine requirement of juvenile Litopenaeus vannamei reared in inland saline water. Seven isonitrogenous (~ 360 g crude protein/kg feed), isolipidic (~ 60 g crude lipid/kg feed) and isocaloric (~ 18 MJ gross energy/kg feed) semi-purified test diets with graded lysine levels viz., 13.7 (L1), 16.3 (L2), 18.7 (L3), 21.4 (L4), 23.8 (L5), 26.3 (L6) and 28.9 g/kg (L7) were formulated and prepared. Three hundred and seventy-eight L. vannamei juveniles (2.75 ± 0.01 g) were randomly distributed (60 no/m3 or 33 no/m2) into seven test groups in triplicates following a completely randomized design. L. vannamei juveniles were fed to the apparent satiation level four times daily. At the end of the feeding trial, the results indicated that dietary lysine levels have significantly (P < 0.05) affected the growth and nutrient utilization parameters in juvenile L. vannamei. An increase (P < 0.05) in final body weight, weight gain percentage (WG%), thermal growth coefficient (TGC), protein efficiency ratio and protein productive value were observed with the increasing dietary lysine levels from 13.7 to 23.8 g/kg after which a decreasing trend was observed. The relative feed intake and feed conversion ratio showed a decreasing trend from lower dietary lysine levels to higher levels. Survival rates of experimented shrimp were not significantly different (P > 0.05) among the treatment groups. The whole body crude protein and crude lipid content of L. vannamei showed significantly (P < 0.05) increasing and decreasing trends, respectively towards the increasing dietary lysine levels. The hepatopancreatic and muscle protein metabolic enzyme activities, haemocyanin and serum total protein content of L. vannamei varied significantly among the treatment groups. The broken-line linear and second-order polynomial regression analysis of WG% and TGC against the dietary lysine levels indicated that the optimal dietary lysine level with confidence interval (CI) for juvenile L. vannamei reared in inland saline water of 10 ppt salinity is 23.46 (22.59–24.88 g/kg, 95% CI) to 25.24 g/kg (24.27–26.53 g/kg, 95% CI) and 23.26 (22.70–24.15 g/kg, 95% CI) to 25.25 g/kg (24.27–26.53 g/kg, 95% CI) of the diet, respectively.

Does tank background colour influence the growth, survival, and carotenoid content in fishes? An illustration in filament barb, Dawkinsia filamentosa (Valenciennes, 1844)

The various environmental factors have a significant impact on cultured species. One such factor influencing larval production in finfish hatcheries is the tank colour. The current study appraised at how different background tank colours such as white, red, blue, green, and black influenced the growth, survival, and body pigmentation of filament barb, Dawkinsia filamentosa. The experiment was conducted for 30 days and the fish were fed with powdered diet thrice a day containing 30% crude protein and 4% crude lipid at satiation level. At the end of study, it was found that the final body length in the black colour tank (15.33 ± 0.17 mm) was significantly (p < 0.05) higher compared to other tank colour groups. In comparison to other treatments, the final body weight (65.17 ± 1.48 mg) and average daily weight gain (1.56 ± 0.05 mg day−1) in the black colour tank was found to be significantly (p < 0.05) higher, while the white colour tank (35.83 ± 1.64 mg; 0.59 ± 0.06 mg day−1) were significantly (p < 0.05) lower. The fish reared in the black colour tank had significantly (p < 0.05) higher specific growth rate (4.22 ± 0.07% day−1) and thermal growth coefficient (19.4 ± 0.6), whereas the white colour tank had the lowest (SGR = 2.24 ± 0.17% day−1; TGC = 7.27 ± 0.71). The survival rate was significantly (p < 0.05) higher in black colour tank (78.33 ± 1.67%) and lowest survival was observed in white tank colour (56.67 ± 3.33%), which represented an improvement of almost 20% for the fishes reared in black colour tank. Fish reared in black tank had the significantly higher level of carotenoid content (2.33 ± 0.08 μg g−1) and fish reared in white tank had lower body carotenoid level (1.02 ± 0.05 μg g−1). It was observed that the different tank colour did not (p > 0.05) cause any change in the stress and non-specific immune parameters of filament barb. Based on the findings, it can be stated that black background colour is the best tank colour for rearing and production of filament barb.

Honey bees can store and retrieve independent memory traces after complex experiences that combine appetitive and aversive associations.

Real-world experiences often mix appetitive and aversive events. Understanding the ability of animals to extract, store and use this information is an important issue in neurobiology. We used honey bees as model organism to study learning and memory after a differential conditioning paradigm that combines appetitive and aversive training trials. First, we used an aversive conditioning paradigm that constitutes a clear opposite of the well-known appetitive olfactory conditioning of the proboscis extension response. A neutral odour is presented paired with the bitter substance quinine. Aversive memory is evidenced later as an odour-specific impairment in appetitive conditioning. Then, we tested the effect of mixing appetitive and aversive conditioning trials distributed along the same training session. Differential conditioning protocols like this were used previously to study the ability to discriminate odours; however, they were not focused on whether appetitive and aversive memories are formed. We found that after differential conditioning, honey bees establish independent appetitive and aversive memories that do not interfere with each other during acquisition or storage. Finally, we moved the question forward to retrieval and memory expression to evaluate what happens when appetitive and the aversive learned odours are mixed during a test. Interestingly, opposite memories compete in such a way that they do not cancel each other out. Honey bees showed the ability to switch from expressing appetitive to aversive memory depending on their satiation level.

Induksi hormon oodev untuk meningkatkan tingkat kematangan gonad ikan cupang betina (Betta splendens) melalui pakan

Betta fish are freshwater ornamental fish that are very popular and have quite high economic value, but the reproductive process still depends on the spawning season, so an increase in reproductive potential is needed. The experiment was conducted in order to determine the role of each induction Oocite development (Oodev) hormone in the diet to betta fish female final maturation process and morphology gonads. Completely randomized design (CRD) with one factor consisting of 5 treatments and 3 replications. The main factors are Oodev hormone dosage: 0.0 mL.kg-1 fish weigh; 0.5 mL.kg-1 fish; 1.0 mL.kg-1 fish; 1.5 mL.kg-1 fish and 2.0 mL.kg-1 fish. We used 135 female broodstock with initial weight range ± 1-2.15 g tail-1 and at stage II of gonad maturation. Fish were fed three a day at 07.00 am, 12.00 am and 05.00 pm at satiation level during 45 days. During the final maturation, gonad morphology, survival rates and water quality were observed. The results show that Oodev hormone induction could improve final maturation up to 266.66%. This result comparatively higher than 0.0 mL.kg-1 and 0.5 mL.kg-1 fish hormone induction, and produce 100% of mature broodstock. Thus, the Oodev hormone induction at optimal dose of 1.16 mL.kg-1 of fish can improve the induction maturation up to 2-3 times faster maturation frequency on the out of spawning season.Keywords: Female Betta splendens; Feed; Final maturation; Oodev

Dietary lysine requirement of genetically improved farmed tilapia (GIFT) juvenile reared in inland saline water of 10 ppt salinity

A 60-day feeding trial was conducted to optimize the dietary lysine (LYS) requirement of juvenile genetically improved farmed tilapia (GIFT) reared in inland saline water (ISW) of 10 ppt salinity. Seven isonitrogenous (370 g crude protein/kg), isolipidic (80 g crude lipid/kg) and isocaloric (16.66 MJ digestible energy/kg) purified diets were formulated and prepared with graded LYS levels viz., 12.3 (L12.3), 14.7 (L14.7), 17.2 (L17.2), 19.6 (L19.6), 22.3 (L22.3), 24.8 (L24.8) and 27.2 g/kg (L27.2). GIFT juveniles (mean weight 3.16 ± 0.01 g, 315 numbers) were randomly allocated in triplicate into seven distinct groups following a completely randomized design. The juveniles were fed three times daily to apparent satiation level with the respective experimental diet. The results indicated that growth and nutrient utilization parameters were significantly (p < 0.05) altered by the various dietary LYS levels. These parameters exhibited an increasing trend from lowest dietary LYS level (12.3 g/kg) to 19.6 g/kg dietary LYS, and subsequent additional dietary LYS supplementation showed a declining trend. Significantly greater final weight, weight gain percentage, specific growth rate, protein efficiency ratio, apparent net protein retention and lower feed conversion ratio were found in the 19.6 g/kg LYS fed group than other groups. Different levels of LYS inclusion did not affect (p > 0.05) the body indices, survival and whole-body moisture and ash content of fish. An increment in dietary LYS up to 19.6 g/kg resulted in an increase in whole-body protein level and a decline in lipid level. The whole-body essential amino acid compositions of juveniles were not changed with various dietary LYS levels, whereas the non-essential amino acids increased with increasing dietary LYS levels up to 19.6 g/kg and decreased thereafter. Juveniles fed with high LYS containing diets exhibited higher aspartate aminotransferase and alanine aminotransferase activities, while digestive enzyme activities were unaffected. Serum protein, albumin, globulin, hemoglobin and white blood cell count changed with various dietary LYS levels. Based on broken-line linear and second-order polynomial regression analysis, the optimal dietary LYS requirements range was found to be 19.3–20.7 g/kg of the diet for GIFT juvenile reared in ISW of 10 ppt salinity.

Induction of Oodev Hormone to increase Gonad Maturity Rate Female Betta Fish (Betta splendens) Through Feed

Betta fish are freshwater ornamental fish that are very popular and have quite high economic value, but the reproductive process still depends on the spawning season, so an increase in reproductive potential is needed. The experiment was conducted in order to determine the role of each induction Oocite development (Oodev) hormone in the diet to betta fish female final maturation process and morphology gonads. Completely randomized design (CRD) with one factor consisting of 5 treatments and 3 replications.The main factors are Oodev hormone dosage: 0.0 mL.kg-1 fish weigh; 0.5 mL.kg-1 fish; 1.0 mL.kg-1 fish; 1.5 mL.kg-1 fish and 2.0 mL.kg-1 fish. We used 135 female broodstock with an initial weight range ± 1-2.15 g.ekor-1 and at stage II of gonad maturation. Fish were fed three a day at 07.00 am, 12.00 am, and 05.00 pm at satiation level during 45 days. During the final maturation, gonad morphology, survival rates, and water quality were observed. The results show that Oodev hormone induction could improve final maturation up to 266.66%. This result is comparatively higher than 0.0 mL.kg-1 and 0.5 mL.kg-1 fish hormone induction and produces 100% of mature broodstock. Thus, the Oodev hormone induction at optimal dose of 1.16 mL.kg-1 of fish can improve the induction maturation up to 2-3 times faster maturation frequency on the out of spawning seasonKeywords:Female Betta splendens; final maturation; Oodev; feed

Effect of skip-feeding and re-feeding regimes on compensatory growth, body composition, feed utilization, feeding cost and survival of monosex tilapia (Oreochromis niloticus) in pond aquaculture system

Monosex tilapia has great acceptability particularly among the lower income people due to its lower price. However, due to increased feed price the price of tilapia has been increased in recent years. Compensatory growth (CG) of fish that is achieved after a period of feed deprivation can potentially reduce the feed cost. The present study aimed to get CG in tilapia farming so as to reduce the production cost of this popular fish. Tilapia fry of 0.54 g body weight were nursed in hapa for one month and then stocked in earthen ponds where two different restricted feeding regimes were imposed for next two months followed by one month feeding at satiation level. Sampling was done fortnightly to record average weight gain in control and treatment groups. Average individual weight in restricted feeding group (T1) reached to 170.11±4.6 g in a three months experimental period and it did not significantly (p&gt;0.05) differ with the weight gained in control group (182.79±5.32 g) where fish were fed on regular basis. The specific growth rate (SGR) also showed no significant difference (p&gt;0.05) between T1 (SGR 2.66±0.011 % day-1) and control group (SGR 2.69±0.012 % day-1). Feed Conversion Ratio (FCR) in T1 (1.26) was found significantly (p&lt;0.05) lower to that of control group (1.47), hence the per unit production cost was also found significantly lower in T1 (BDT 75 Kg-1) compared to that of control (BDT 88.23 Kg-1). On the other hand no significant difference was evident in biochemical parameters between the control and restricted feeding groups. Thus, this study suggests skip feeding as an appropriate tool to achieving CG in monosex tilapia and to trim down the production cost as well.&#x0D;

Mannan Oligosaccharide Enhanced the Growth Rate, Digestive Enzyme Activity, Carcass Composition, and Blood Chemistry of Thinlip Grey Mullet (Liza ramada).

Simple SummarySustainable aquaculture requires natural alternative substances with high potential in enhancing the performance and wellbeing of aquatic animals. In this regard, the present study tested the possibility of using mannan oligosaccharides (MOS) in the diets of grey mullet as functional additives. For 8 weeks, fish were fed with enriched diets containing 0, 0.5, 1, and 2% MOS. The results showed marked improvements in the growth performance, digestive enzyme activity, blood chemistry, and antioxidative capacity. In conclusion, dietary MOS at 0.5–1% is required to enhance the productivity of grey mullet.Mannan oligosaccharide (MOS) is prebiotic with high functionality in aquaculture. The current study investigated the potential roles of MOS on the growth performance, digestive enzyme activity, carcass composition, and blood chemistry of Thinlip grey mullet (Liza ramada). Four tested diets with 34.49% crude protein and 6.29% of total lipids were prepared and fortified with 0, 0.5, 1, and 2% MOS. Fish of initial weight = 5.14 ± 0.11 g/fish were distributed in 12 hapas (0.5 × 0.5 × 1 m) at 15 fish per hapa (triplicates) and fed the test diets to the satiation level two times a day (08:00 and 15:00) for eight weeks. At the end of the trial, all fish were weighed individually for growth performance calculation. Blood was collected to check blood chemistry traits, and intestines were dissected for digestive enzyme analysis. Fish treated with MOS had marked enhancement in the final body weight, feed conversion ratio, protein gain, and protein retention regardless of inclusion dose (p < 0.05). The weight gain, specific growth rate, and protein efficiency ratio were meaningfully enhanced by including MOS at 0.5 and 1%, followed by fish fed with 2% MOS, while the lowest values were in the control group (p < 0.05). Insignificant influences of MOS were seen on the chemical composition of carcass components (moisture, crude protein, total lipids, and ash) (p > 0.05). Fish treated with MOS at 0.5 and 1% had marked enhancement in the amylase, lipase, and protease activities regardless of inclusion dose (p < 0.05). The blood total protein and albumin levels were meaningfully enhanced by including MOS at 0.5 and 1%, followed by fish fed with 2% MOS, while the lowest values were in the control group (p < 0.05). The blood globulin was significantly enhanced in fish fed 1% MOS than fish treated with 0, 0.5, and 2% of MOS (p < 0.05). The blood lysozyme activity was meaningfully enhanced by including MOS at 1%, followed by fish treated with 0.5 and 2%, while the lowest values were in the control group (p < 0.05). Phagocytic activity and phagocytic index were markedly improved in fish treated with 1 and 2% MOS, followed by those fed 0.5% compared with fish fed MOS-free diet (p < 0.05). Superoxide dismutase and glutathione peroxidase were markedly improved in fish treated with 1, and 2% MOS, followed by those fed 0.5% compared with fish fed MOS-free diet (p < 0.05). Dietary MOS (0.5, 1, and 2%) meaningfully enhanced catalase activity while decreased the malondialdehyde concentration (p < 0.05). In summary, dietary MOS is required at 0.5–1% for enhancing the growth rate, feed efficiency, digestive enzyme activity, blood chemistry, and antioxidative capacity of grey mullet.