Allometric growth patterns and development in larvae and juveniles of thick‐lipped grey mullet Chelon labrosus reared in mesocosm conditions

Allometric growth and ontogeny were studied in thick‐lipped grey mullet Chelon labrosus reared in mesocosms from 1 to 71 day post hatching (dph). Multivariate allometric analysis of morphometric growth distinguished three distinct developmental stanzas separated by two morphometric metamorphosis lengths (L_m1 = 4.46 ± 0.06 mm; L_m2 = 28.56 ± 1.04 mm). Body mass growth also showed three distinct episodes separated by two inflections, correlated with morpho‐functional changes. First episode concerned pre‐flexion larvae and ended around 4.5 mm‐L_T (14‐dph), coinciding with estimated L_m1. It was distinguished by reduced growth, but intense morphogenesis and differentiation processes. Organogenesis and allometric changes indicated that development priorities concerned feeding efficiency, by improving detection ability (sensory system development), ingestion capacity (head growth) and assimilation performance (digestive system differentiation), together with respiration efficiency (gill development). Second episode concerned post‐flexion larvae and, ended around 8.6 mm‐L_T (25‐dph). It was distinguished by fast growth of trunk and tail, acquisition of adult axial muscle distribution and completion of gill filament development, improving locomotion and oxygenation performances. It corresponded to transition towards metamorphosing stage as indicated by later isometric growth, musculature maturation and acquisition of juvenile phenotype. Metamorphosis seemed to end at L_m2, suggesting to avoid zootechnic handling before this size.     

Ontogeny of the digestive tract of thick lipped grey mullet (Chelon labrosus) larvae reared in “mesocosms”

This work describes the ontogeny of the digestive tract in thick lipped grey mullet (Chelon labrosus) larvae reared until day 36 post-hatching with the semi-extensive technology in mesocosms. Diet was constituted by live preys, rotifers, Artemia and wild zooplankton, then compound diet was added from day 20 (p. h.). Linear growth, weight growth and digestive enzymes specific activities were studied during larval ontogeny. Pancreatic enzymes (trypsin and amylase) and intestinal enzymes (leucine-alanine peptidase “Leu-ala”, aminopeptidase N “AN” and alkaline phosphatase “AP”) were assayed in larvae sampled throughout the rearing trial to evaluate gastrointestinal maturation along the development.The trypsin specific activities were very high during the first two weeks and then declined as observed in marine fish species. A following increase in trypsin specific activity from day 20 was attributed notably to ingestion of particle compound diet. In contrast to the pattern generally described in fish larvae, amylase specific activity showed a continuous increase. This could be attributed to the fact that C. labrosus is an omnivorous species and suggests that the fish might be able to use efficiently diets containing higher levels of starch or other carbohydrates since the end of larval development.Relative expression of intestinal brush border membrane enzymes (AP and AN) and cytosolic enzyme (Leu-ala), showed an abrupt increase of both AP/leu-ala and AN/leu-ala ratios at day 8 (p. h.), indicating that maturation of intestinal tract in C. labrosus larvae is particularly precocious. It is assumed that larvae of C. labrosus might support early co-feeding and weaning strategies, which could reasonably be initiated since mouth opening.     

Effects of dietary supplementation of probiotics on the growth,activities of digestive and non‐specific immune enzymes in hybrid grouper (Epinephelus lanceolatus ♂ × Epinephelus fuscoguttatus ♀)

Effects of Bacillus cereus BC‐01, Lactobacillus acidophilus LAG01, Clostridium butyricum CBG01 and their combinations as supplementation on the growth performance, digestive enzyme activities and serum non‐specific immunity of hybrid grouper (Epinephelus lanceolatus ♂×E. fuscoguttatus ♀) were assessed. Seven different diets, that is one control diet (basal feed without any probiotics, CT) and six treatment diets containing single B. cereus (Bs), L. acidophilus (Ls) and C. butyricum (Cs) at 1.0 × 10⁹ cfu/kg feed, and also their combinations in equal proportion at 1.0, 2.0 and 3.0 × 10⁹ cfu/kg feed (BLC1, BLC2 and BLC3) were prepared respectively. After 60‐day feeding trial, the final weight, specific growth rate,food consumption, food conversion efficiency and apparent digestibility coefficient of fish in Ls and BLC3 were significantly higher compared with the control (p < .05). The activities of pepsin and trypsin in the intestine of fish for Ls and BLC3 were significantly higher relative to the control (p < .05). Relative to controls, significantly enhanced amylase and lipase activities in proximal intestine except for Cs and BLC1 and lipase activities in distal intestine except for Cs were observed (p < .05). Meanwhile, activities of superoxide dismutase in the serum of fish for all treatments, lysozyme and catalase in Ls and BLC3, and glutathione peroxidase except for Cs were significantly enhanced (p < .05). Based on the above, dietary supplementation of single L. acidophilus at 1.0 × 10⁹ cfu/kg or combination of three strains at 3.0 × 10⁹ cfu/kg for hybrid grouper is recommended.     

Partial characterization of digestive proteases of the three‐spot cichlid Cichlasoma trimaculatum (Günter 1867)

Partial characterization of digestive proteases in the three‐spot cichlid Cichlasoma trimaculatum juveniles was conducted. It was determined that there is higher alkaline proteases activity (3.95 ± 0.32 IU mg^?1 protein) compared to acidic proteases (2.01 ± 0.57 IU mg^?1 protein). Optimal temperature for alkaline proteases is 60 °C which resulted in more thermostability to temperature changes. On the other hand, optimal temperature for acidic proteases is 50 °C. Optimal pH for acidic proteases was pH 2, while for alkaline proteases, it was pH 10, which resulted in more stability in relation to pH changes than acidic protease. The use of specific inhibitors and the SDS‐PAGE electrophoresis analysis revealed seven types of bands for alkaline proteases, which make evident the main presence of serine proteases. In acidic proteases, more than 98 g kg^?1 of the activity was inhibited with pepstatin A inhibitor. Therefore, it is evident that C. trimaculatum digestion is composed by acidic and alkaline proteases; thus, it should be considered an omnivorous fish.     

Effect of probiotics on digestive enzyme activities and growth of cichlids,Etroplus suratensis (Pearl spot) and Oreochromis mossambicus (Tilapia)

In aquaculture, exposure to stressful conditions and problems related to diseases often occur resulting in serious economic loss. The use of probiotics that control pathogens through different mechanisms, aiding digestion by exoenzyme supply and establishment of beneficial microflora in the digestive tract has got increased attention recently. Two different bacterial species Micrococcus MCCB 104 and Bacillus MCCB 101 were tested as probiotics for two cichlid species Etroplus suratensis and Oreochromis mossambicus. The strains were administered separately and together, at a rate of 10³ CFU animal^?1 day^?1 for 28 days. The effects on digestive enzyme activity and growth were compared with those fed on control diet. FCR of E. suratensis was high in case of Bacillus alone as well as the mixed culture (Micrococcus and Bacillus together) than that of control. However, the SGR of E. suratensis was slightly lower than that of control during 14 days trial. SGR of both the treatments (Bacillus alone and mixed culture) was higher than that of the control on 28th day, and this might be due to the reason that specific duration is needed for the assimilation and conversion of nutrients into proteins. The intestinal digestive hydrolases of E. suratensis were profoundly enhanced mainly by Bacillus and mixed cultures. The hepatopancreatic versions of major digestive enzymes in E. suratensis were influenced variously by different probiotic treatments. The alpha‐amylase activity of hepatopancreas has been elevated significantly by mixed culture during 14 days experiments while on 28 days trials both Bacillus and mixed culture showed an enhancing effect. During 14 days feeding trials, the intestinal lipase activity has been prominently enhanced by all probiotic treatments. It is found that, in O. mossambicus, both 14 days and 28 days feeding experiments, the pepsin as well as intestinal digestive enzymes such as amylase, total alkaline protease, lipase and their hepatopancreatic counter parts showed a significant elevation in their specific activity. Intestinal alpha‐amylase and total alkaline proteases of O. mossambicus showed an increase in specific activities on both 14 days and 28 days feeding experiments with the Bacillus and Micrococcus combination. The hepatopancreatic enzymes were highly influenced by the Bacillus species in O. mossambicus. The results of this study suggest that live probiotic microorganisms such as Micrococcus MCCB 104 and Bacillus MCCB 101 may be incorporated while formulating the cost‐effective, nutritionally balanced diet of E. suratensis and O. mossambicus for better growth performance and nutrient utilization.     

Replacement of fish oil with a DHA‐rich Schizochytrium meal on growth performance,activities of digestive enzyme and fatty acid profile of Pacific white shrimp (Litopenaeus vannamei) larvae

This trial was conducted to evaluate the effects of replacing dietary fish oil with Schizochytrium meal for Pacific white shrimp (Litopenaeus vannamei) larvae (initial body weight 4.21 ± 0.10 mg). Six test microdiets were formulated using Schizochytrium meal to replace 0 g/kg, 250 g/kg, 500 g/kg, 750 g/kg, 1000 g/kg or 1500 g/kg fish oil DHA. No significant differences were observed in survival, growth, final body length and activities of digestive enzyme among shrimp fed different diets (p > .05). No significant differences were observed in C20:5n‐3 (EPA) in muscle samples (p > .05). C18:3n‐3 and C20:4n‐6 in muscle increased as Schizochytrium meal replacement level increased (p < .05). No significant differences were observed in C22:6n‐3 (DHA) and n‐3 fatty acids among shrimp fed diets that algae meal replaced 0 g/kg ‐ 1000 g/kg of fish oil. Shrimp fed diet R150 had higher DHA content than other groups and had higher n‐3 fatty acids than that of shrimp fed diets R50, R75 and R100 (p < .05). C18:2n‐6, PUFA and n‐6 fatty acids in muscle increased, while n‐3/n‐6 ratio decreased with increasing algae meal replacement level from 0 g/kg to 1000 g/kg (p < .05). In conclusion, Schizochytrium meal could replace 1500 g/kg fish oil DHA in the microdiets without negatively affecting shrimp larvae survival, growth and activities of digestive enzyme.     

Effects of docosahexaenoic acid on growth,survival and swim bladder inflation of larval amberjack ( Seriola dumerili, Risso)

The effect of docosahexaenoic acid (DHA) on the growth performance, survival and swim bladder inflation of larval Seriola dumerili during the rotifer feeding period was investigated in two feeding experiments. Amberjack larvae at 3 day post hatching were fed rotifers enriched with (1) freshwater C hlorella (Chlo), (2) a mixture (2:1, v/v) of Chlo and DHA‐enriched C hlorella (DHA‐Chlo), (3) DHA‐Chlo and (4) DHA‐Chlo and commercial DHA emulsion, in triplicate for 7 days. The average DHA contents of the rotifers were 0.0, 0.4, 1.0 and 1.9 mg g^?1 DM respectively. The survival rate was improved by the enrichment of rotifers with DHA‐Chlo alone, and DHA‐Chlo and emulsion. Growth and swim bladder inflation of fish fed rotifers enriched with DHA‐Chlo were significantly (P < 0.05) improved, however, with increased levels of DHA further improvement was not found. DHA content in the larval whole body proportionally increased with the DHA level in the rotifers. These results suggest that DHA enrichment of rotifers is effective to improve the growth, survival rate and swim bladder inflation of amberjack larvae. The DHA requirement of amberjack larvae is estimated to be 1.5 mg g^?1 on a dry matter basis of rotifers.     

Ontogenic changes in the digestive enzyme activities and the effect of different starvation duration on the digestive enzyme activities of larval red swamp crayfish (Procambarus clarkii)

This study was performed to determine the effect of starvation and delayed feeding on activities of digestive enzymes and alkaline phosphatase (ALP) of larval red swamp crayfish (Procambarus clarkii), so as to reveal the tolerance to prolonged starvation and the recovery of digestive enzymes after delayed feeding in larval and juvenile P. clarkii. In the control group, activities of trypsin and ALP increased significantly (p < .05) with day‐age and then kept constant at 24 days after hatching (DAH) and 10 DAH, respectively, whereas the activities of amylase and pepsin increased firstly then decreased with day‐age, and the activity of lipase increased firstly then decreased and then increased again during the development period of juvenile P. clarkii (1–31 DAH). In the group with continuous starvation (CS), activities of pepsin and lipase both decreased (p < .05) after fasting, and the activities of pepsin, lipase and trypsin in the groups with delayed feeding all increased (p < .05) and recover to the levels of the control group after food supply. However, the activity of amylase increased (p < .05) in the CS group, and it decreased to normal level after food supply. The ALP activity did not significantly (p > .05) vary after starvation, whereas it decreased in the groups with delayed feeding after 1 day of food supply, and then increased back to the level similar with the control group. Results from this study could provide information for diet preparation and feeding regime in larval and juvenile red swamp crayfish culture.     

Effects of native medicinal herbs (Alternanthera sessilis,Eclipta alba and Cissus quadrangularis) on growth performance,digestive enzymes and biochemical constituents of the monsoon river prawn Macrobrachium malcolmsonii

The medicinal herbs such as Alternanthera sessilis, Eclipta alba and Cissus quadrangularis were used to assess the growth promoting ability, enhancement of muscle biochemical constituents and profiles of amino acid in the freshwater prawn, Macrobrachium malcolmsonii. The herbal powders were separately incorporated with basal diet, and these diets were fed to M. malcolmsonii postlarvae for a period of 90 days. At the end of experiments, the survival of prawn significantly improved in herbal incorporated feed. In addition, the growth parameters, such as weight gain, specific growth rate and protein efficiency rate were significantly (P < 0.05) higher in herbal diets fed groups when compared with control. The activities of digestive enzyme, biochemical constituents, profile of amino acid, energy utilization parameters, concentrations of vitamin C and E were significantly (P < 0.05) elevated in experimental diets fed groups when compared with control. The profiles of essential amino acids were also found elevated in herbal incorporated diets fed PL. Among the three herbs tested, C. quadrangularis incorporated diet fed group showed better performance followed by the E. alba and A. sessilis. The present study suggests that these herbs can be incorporated in artificial feed formulations for Macrobrachium culture.     

Effect of short‐term fasting and re‐feeding on growth,digestive enzyme activities and antioxidant defence in yellowfin seabream,Acanthopagrus latus (Houttuyn, 1782)

An 80‐day feeding trial was conducted to evaluate the influence of different short‐term fasting and re‐feeding strategies on growth and physiological responses in yellowfin seabream, Acanthopagrus latus (2.4 ± 0.2 g) fingerlings. The fish were subjected to four different feeding regimes, and the control group fed four times daily to apparent satiation throughout the whole feeding period, while the other three groups were deprived for 2, 4 and 8 days followed by 8, 16 or 32 days of re‐feeding (F₂R₈, F₄R₁₆ and F₈R₃₂, respectively) in repeated cycles for 80 days. The fish in the control and F₂R₈ groups had the highest and the lowest total length, respectively (p < .05). Moreover, fish exposed to F₄R₁₆ had the highest hepatosomatic indices, while control fish had the lowest hepatosomatic indices (p < .05). Fish in the F₂R₈ group relatively had higher catalase and glutathione‐S‐transferase activities than other groups (p < .05). Furthermore, total protease, α‐amylase and alkaline phosphatase activities in the F₄R₁₆ and F₈R₃₂ were higher than the F₂R₄ and control groups (p < .05). Overall, this study showed that compensatory growth in weight and length and digestive enzyme activities were observed in the F₄R₁₆ and F₈R₃₂; however, the increase in the activity of antioxidant enzymes in the F₈R₃₂ group indicated that oxidative stress remained after 80 days of re‐feeding in the liver.     

Effect of dietary protein levels on growth and nutrient utilization of fringe‐lipped carp,Labeo fimbriatus (Bloch) fingerlings

Effect of various dietary protein levels on growth and nutrient utilization were studied in fringe‐lipped carp, Labeo fimbriatus fingerlings for 60 days. Five practical diets containing graded protein levels of 200, 250, 300, 350 and 400 g kg^?1 with respective digestible protein (DP) contents of 192.4, 244.5, 291.6, 339.4 and 391.4 g kg^?1 were evaluated as five treatments, T1, T2, T3, T4 and T5, respectively, in triplicate. Each experimental tank (80‐L) contained eight fingerlings (4.9 ± 0.1 g) and was subjected to continuous aeration and 25% water replenishment daily. The fish were fed two times daily at 8:00 and 14:00 h to satiation. Significantly higher (P < 0.05) absolute growth and thermal growth coefficient, and lower feed conversion ratios (FCR) were observed in T2–T4 than T1 and T5. Protein efficiency ratio (PER) and protein productive values (PPV) were highest in T2 and lowest in T5. Significantly higher (P < 0.05) apparent protein digestibility was perceptible in T2–T4. While specific amylase activity declined linearly with increasing DP : DE, the protease, trypsin, aspartate aminotransferase and alanine aminotransferase established polynomial relationship. Based on live weight gain, PER and PPV fitted to quadratic model optimum DP levels were estimated as 301.4, 260.0 and 273.0 g kg^?1, respectively.     

Cross‐effects of dietary probiotic supplementation and rearing temperature on growth performance,digestive enzyme activities,cumulative mortality and innate immune response in seabass (Dicentrarchus labrax)

Probiotic influence on fish immune response and digestive capacity is extensively discussed in aquaculture. In this experiment, a feeding trial was carried out for 100 days to evaluate the cross‐effects of probiotic supplementation and rearing temperature (17, 20 and 23°C) in juvenile seabass (Dicentrarchus labrax). The experimental diet was supplemented with a commercial probiotic blend (Biomin AquaStar Growout) at 3 g/kg diet (5.23 × 10⁸ CFU/kg diet), and tested against a non‐supplemented diet (control). Growth performance and innate immune responses were analysed at 70 and 100 days of feeding, whereas digestive enzyme activities were determined at 100 days of feeding. At the end of the feeding trial, fish were subjected to a handling stress and cumulative mortality was recorded. Digestive enzyme activities were influenced by temperature, with α‐amylase and lipase activities peaking at the higher temperature (23°C) and trypsin at the lower temperature (17°C). Immune parameters showed a significant temperature versus feeding duration effect, with complement system (ACH50) and peroxidase peaking at 70 and 100 days of feeding, respectively. Poststress cumulative mortality was higher at the lowest temperature (17°C), especially in fish fed the control diet. In conclusion, water temperature was the main variable affecting the studied parameters, whereas the dietary probiotic supplementation had influence on the chymotrypsin activity and survival rate in seabass reared at 17°C.     

The responses of digestive enzymes in juvenile and adult Rapana venosa (Valenciennes, 1846) to different temperatures

The veined rapa whelk, Rapana venosa (Valenciennes, 1846), is an important and valuable fishery species; however, it has not been routinely artificially cultured on a large scale. Here, we studied the effect of temperature (6, 16, 22 and 28°C) on the digestive enzymes in R. venosa of different sizes (Juvenile (small, S: 1.2–1.8 cm) and adult (medium, M: 4.1–5.2 cm; large, L: 7.6–8.9 cm)) by detected the enzyme activity in different digestive glands (the salivary gland, Leiblein's gland (oesophageal gland) and liver) using spectrophotometric method, to determine the optimal temperature for artificial cultivation and to explore the feeding habits of this whelk. The optimal temperature was determined to be approximately 22°C. The food intake was significantly higher at 22°C than at other temperatures, and the activity of the digestive enzyme, trypsin, was at the highest in the main digestive gland of R. venosa, the liver, at 22°C. In addition, the observed presence of cellulase and α‐amylase may suggest that carbohydrates are necessary during R. venosa development. The results of this study will help in the formulation of technical procedures for R. venosa aquaculture and in preventing its overexploitation, and explained its invasion mechanism to some extent.     

Efficacy of calcein as a chemical marker of green‐lipped mussel (Perna canaliculus) larvae and its potential use for tracking larval dispersal

An optimal chemical shell marking protocol was developed for the New Zealand green‐lipped mussel, Perna canaliculus with a view to its future use in larval tracking experiments. Larval P. canaliculus aged either 10, 15 or 19 days post fertilization were immersed in treatments of 50, 100 and 200 mg L^?1 of calcein for a period of 24 h before measurements of shell mark brightness were taken. There was 100% marking success in all calcein treatments for all age classes, with 19‐day larvae immersed in 200 mg L^?1 calcein producing the brightest mark. Growth was not affected by calcein immersion; however, 10‐day larvae exhibited significantly higher levels of mortality compared with 15‐ and 19‐day larvae suggesting a reduced resilience to the marking protocols in younger larvae. In a mass staining experiment, a solution of 100 mg L^?1 calcein was used to successfully stain15.6 million hatchery reared P. canaliculus larvae. Calcein, therefore, offers a low impact method with which to stain the sensitive early life stages of this species thus providing a rapid method for identifying individuals of interest, i.e. individuals released in the wild or specific family lines within a hatchery environment.     

Effects of different dietary carbohydrate‐to‐lipid ratios on growth,plasma biochemical indexes,digestive and immune enzymes activities of juvenile orange‐spotted grouper Epinephelus coioides

An 8‐week feeding trial was conducted to investigate the effects of dietary carbohydrate‐to‐lipid (CHO:L) ratios on growth, liver and muscle glycogen content, haematological indices, and liver and intestinal enzyme activity of juvenile grouper (Epinephelus coioides). Five isonitrogenous (496.0 g/kg protein) and isoenergetic (21.6 KJ/g gross energy) diets with varying CHO:L ratios of 0.65 (D1), 1.31 (D2), 2.33 (D3), 4.24 (D4) and 8.51 (D5), respectively, were fed to triplicate groups of 20 fish (average 10.02 ± 0.1 g) for 8 weeks. Results showed that the weight gain rate, specific growth rate and protein efficiency ratio (PER) of juvenile grouper increased first and then decreased with the increase in CHO:L ratio, reaching a maximum value in the D4 (CHO:L = 4.24) diet. The trend for the feed conversion ratio was opposite to the PER. Along with the diet CHO:L ratios, the apparent digestibility coefficients (ADC) of crude lipid and energy for the juvenile groupers decreased gradually, while the ADC of dry matter, liver and muscle glycogen level increased gradually. Total protein, triglycerides and cholesterol in serum were all maximized in the D4 diet and glucose in the D5 (CHO:L = 8.51) diet. Digestive enzyme activity in the intestine was significantly affected by dietary CHO:L ratio. Liver hexokinase, phosphofructokinase and glucose‐6‐phosphate dehydrogenase activity increased significantly as CHO:L ratio increased. Liver lysozyme and acid phosphatase activity in the groupers fed the D3 (CHO:L = 2.33) diet was significantly higher than that of other diets. Liver fructose‐1,6‐bisphosphatase and alkaline phosphatase activity reached a maximum value in the D4 diet and was significantly higher than that in the D1 diet. Taking the above results together, it can be concluded that an optimal dietary CHO:L ratio of 2.33 is suitable for grouper culture concerning growth performance and health.     

Age‐dependence of cultured pearl grade and colour in the black‐lipped pearl oyster Pinctada margaritifera

Pinctada margaritifera is an economically important marine bivalve species for cultured pearl production in French Polynesian aquaculture. In order to evaluate the influence of donor oyster age on pearl quality traits, experiments were conducted over 6 years using both grafts and surgreffe operations. At harvest, six pearl quality traits were recorded and compared: surface defects, lustre, grade, darkness level and visual colour. Analysing the quality traits of pearls harvested in the initial graft process and those of pearls obtained from surgreffe experiments allowed a comparison of the influence of pearl sac cells originating from the initial mantle graft, which aged together with their recipient oysters. The results demonstrated a significant decrease between these successive grafts in lustre, grade (A‐B‐C), darkness level, and green colour – traits that are of major importance in the pearl market. The duplicated graft experiment allowed the comparison of donor oyster families at 2 and 5 years old, where a mantle graft was inserted into recipient oysters aged 2.5 years. The results showed the same tendencies to a lesser extent, with (i) an improved pearl grade, predominantly through a most important rate of 0 surface defect category, and (ii) a green/grey ratio in favour of the younger donor. A comparison between the graft‐surgreffe and the duplicated graft experiments also highlighted: (i) the indirect role played by the younger recipient oysters, which must be optimized for optimal pearl quality realization, and (ii) the complex interplay between the donor and recipient oysters.     

Improvement of growth performance,digestive enzymes and body composition of Persian sturgeon (Acipenser persicus) following feeding on probiotics: Bacillus licheniformis,Bacillus subtilis and Saccharomyces cerevisiae

The individual and combinational effects of probiotics on Persian sturgeon (Acipenser persicus) were evaluated through assessing the growth performance, proximate body composition, digestive enzymes and intestinal morphology. On the basis of feeding with experimental diets, the fish were assigned into four groups denoted as follows: control (basal diet), D‐Pro (basal diet + Bacillus subtilis and Bacillus licheniformis), D‐Pro/Yeast (basal diet + B. subtilis and B. licheniformis + Saccharomyces cerevisiae), Yeast (basal diet + S. cerevisiae). Maximum mean weight and length were measured for the fish fed with D‐pro regime. weight gain (WG), body weight gain (BWI%),  feed efficiency (FE%), protein efficiency rate (PER), lipid efficiency rate (LER), and condition factor (CF) demonstrated the highest values for the fish fed with the diets containing D‐Pro and/or D‐Pro/yeast. LER and food conversion ratio (FCR) showed the highest performance for the fish received the D‐Pro diet. The diets containing D‐Pro exhibited higher performance in enhancing the activity of protease and lipase than the one supplemented only with the yeast, whereas the regimes treated with the yeast exhibited higher amylase activity. The fish received D‐Pro exhibited the highest protein and fat contents, yet did the lowest contents of moisture and total ash. Taken together, the findings revealed that the dietary administration of the D‐Pro and D‐Pro/Yeast could improve the growth performance of A. persicus.