高HCO3-浓度对细基江蓠繁枝变型生长及生理生化特征的影响

为探讨高碳酸盐碱度水质对江蓠的影响, 本研究对比分析了高HCO₃^-浓度(12、24、36、48 mmol/L)与低HCO₃^-浓度(1.8 mmol/L)条件下细基江蓠繁枝变型(Gracilaria tenuistipitata var. liui Zhang et Xia)的生长及生理生化特征。经过10 d的培养后发现高HCO₃^-浓度组中江蓠的特定生长率(SGR)显著高于对照组(P<0.05), 表明高HCO₃^-浓度有利于促进江蓠的生长。随着HCO₃^-浓度的增加, 江蓠的叶绿素a、藻红素、类胡萝卜素含量呈逐渐下降趋势, 丙二醛含量呈增加趋势。当HCO₃^-浓度从1.8 mmol/L增加到24 mmol/L时, 江蓠SGR、超氧化物歧化酶(SOD)和过氧化物酶(POD)活性呈增加的趋势, 而从24 mmol/L增加到48 mmol/L时, 这3种指标均呈下降趋势。相关分析表明, 江蓠SGR与SOD活性呈显著的正相关关系(P<0.05), 说明HCO₃^-浓度的增加对江蓠生长产生一定胁迫作用, 但其具有由抗氧化酶形成的自身防御系统, 能够在一定HCO₃^-浓度范围内保护藻体。在本实验条件下, 江蓠对高HCO₃^-离子具有较强的耐受能力, 其生长的最适HCO₃^-浓度为24 mmol/L, 超过这一浓度对江蓠生长的促进作用有所减弱。本研究旨在通过探讨大型海藻对高HCO₃^-浓度的生长及生理生化适应性, 为运用大型经济海藻对高碳酸盐型盐碱水域开发利用的可行性提供科学依据。

     

CO_2浓度对细基江蓠繁枝变型生长和光合特性的影响

比较了低CO_2浓度(充无CO_2空气,low CO_2,简称LC)、正常CO_2浓度(充正常空气,normal CO_2,简称NC)、高CO_2浓度(充正常空气+0.2%CO_2,high CO_2,简称HC)3种条件下细基江蓠繁枝变型(Gracilaria tenuistipitata var.liui Zhang et Xia)的特定生长率、光合色素含量、光合放氧速率和叶绿素荧光参数。结果表明:培养6 d后,与NC组相比,LC组细基江蓠繁枝变型特定生长率(SGR)、100μmol·(m~2·s)~(-1)光强净光合放氧速率及PSII最大光量子产率(Fv/Fm)均显著降低(P0.05);类胡萝卜素含量显著增加(P0.05);而藻红素、叶绿素a含量、PSII实际光量子产率(Fv/Fo)、快速光响应曲线初始斜率(α)、最大电子传递效率(ETR_(max))及半饱和光强(I_k)均无显著差异(P0.05)。与NC组相比,HC组细基江蓠繁枝变型的SGR、Fv/Fm及α显著增加(P0.05),藻红素含量显著下降(P0.05),而叶绿素a、类胡萝卜素含量、600μmol·(m~2·s)~(-1)光强净光合放氧速率、Fv/Fo、α、ETR_(max)及I_k均无显著差异(P0.05)。与LC组相比,HC组细基江蓠繁枝变型的100μmol·(m~2·s)~(-1)光强净光合放氧速率、SGR、Fv/Fm、Fv/Fo、α均显著增加(P0.05),而藻红素、叶绿素a、类胡萝卜素含量却显著下降(P0.05),600μmol·(m~2·s)~(-1)光强净光合放氧速率、ETR_(max)、I_k无显著变化(P0.05)。对于细基江蓠繁枝变型,CO_2浓度升高降低了光合色素含量,同时提高了光系统光能转换效率,而对藻体饱和光强下净光合放氧速率的促进作用不显著。但是CO_2浓度升高却仍然可能通过降低无机碳利用的能量消耗及提高营养盐吸收利用而显著促进藻体的生长。比较不同CO_2浓度下细基江蓠繁枝变型生长和光合特性的差异,有助于初步揭示其对大气CO_2浓度变化的响应特征。     

Effect of natural pigment sources on colouration of red zebra cichlid (Maylandia estherae Konings, 1995)

This study was done to assess the effect of the colouration of the red zebra cichlid (Maylandia estherae), using beet root red (Beta vulgaris ruba) and henna (Lawsonia inermis). The fish with an average weight of 1.21 ± 0.69 g was placed in 12 aquariums. Fifteen fish were placed in each aquarium. The fish were fed with diets which were without carotenoid supplement (AK), containing astaxanthin (AA), beet root red (AP) and henna (AI). Except the AK, each group contained 50 mg/kg carotenoid additives. As a result of the experiment, total carotenoid values between groups were not significant (p > .05). The redness (a*) value of groups was significant (p < .05), and the values of brightness (L*) and yellowness (b*) were not significant (p > .05). Samples were kept in the freezer at ?20°C for 120 days to see whether the fish kept their colour. All groups decreased compared with the 50th day. This difference in groups except the AP was significant (p < .05). The FCR, SGR and weight gain% was not significant (p > .05). The survival was 97.28%, and it was the same in all groups. The study concluded that natural carotene sources with lower costs had similar effects with astaxanthin.     

The effects of tank colours on the growth and survival of cuttlefish (Sepia officinalis,Linnaeus 1758) hatchlings and juveniles

The effects of different tank colours (white, yellow sandy and black) on the growth, mortality and biomass production were studied for hatchling and early juvenile cuttlefish. For hatchlings, the use of different colour tanks did not promote differences in growth due to the higher variability (standard deviation) found in the white‐ and sand‐coloured tanks. Black tanks promoted the lowest and highest values for total mortality and biomass respectively. For juveniles, the use of different tank colours promoted different growth (P<0.05), but not mortality. Black tanks promoted the best results in terms of growth and biomass. The results obtained in the present study advise the use of black (or dark colour) tanks in the hatchling and early juvenile stages to reduce the standard deviations associated with growth, mortality and biomass production. This will contribute to minimize problems associated with slow and fast growers and competition.     

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.     

Effect of Lactobacillus plantarum and Jerusalem artichoke (Helianthus tuberosus) on growth performance,immunity and disease resistance of Pangasius catfish (Pangasius bocourti,Sauvage 1880)

This study evaluated the effects of Jerusalem artichoke (JA) and Lactobacillus plantarum singly or combined on growth, immunity and disease resistance of Pangasius bocourti. In the first experiment, different concentrations of JA (0, 5, 10, 20, 40, 80 and 160 g kg^?1) were administered to determine an optimal concentration on growth of P. bocourti. In the second experiment, the optimal concentration of JA (5 g kg^?1) was combined with 10⁸ cfu g^?1 L. plantarum. In the final experiment, five randomly selected fish from the second experiment were challenged with Aeromonas hydrophila. Treatments for second and third experiments were 0 g kg^?1 JA (Diet 1), 5 g kg^?1 JA (Diet 2), 10⁸ cfu g^?1 L. plantarum (Diet 3) and 5 g kg^?1 JA + 10⁸ cfu g^?1 L. plantarum (Diet 4). Fish fed 5 g kg^?1 JA or 10⁸ cfu g^?1 of L. plantarum significantly improved specific growth rate (SGR), feed conversion ratio (FCR), serum lysozyme activity and postchallenge survival rate (PCSR). Dietary in the combination of JA and L. plantarum showed significantly enhanced SGR, FCR, serum lysozyme, phagocytosis, respiratory burst activities and PCSR compared with control and individual applications. Dietary JA and L. plantarum significantly stimulated growth, immunity and disease resistance of P. bocourti.     

Lutein as a natural carotenoid source: Effect on growth,survival and skin pigmentation of goldfish juveniles (Carassius auratus)

This study aimed to evaluate the effect of lutein supplementation on growth, survival and skin pigmentation for goldfish juveniles. Four diets enriched with different carotenoid sources (lutein, astaxanthin, canthaxanthin and a combination of lutein and canthaxanthin) were compared to a control diet without carotenoid supplementation. The carotenoid inclusion level was standardized at 50 mg kg‐1 in all treatments. 240 goldfish juveniles (1.07?0.57 g) were cultivated in 30 aquariums (30L) during 84 days. The experimental design was completely randomized with five treatments and six replicates. The dietary inclusion of carotenoid pigments did not affect the growth and feeding efficiency of goldfish juveniles. Supplementation with lutein presented higher survival values when compared to the other treatments. Astaxanthin and canthaxanthin supplementation increased the concentration of carotenoids on the skin of goldfish juveniles in relation to the control treatment. For the fish fed with the diet containing lutein, the skin pigmentation was as efficient as astaxanthin and canthaxanthin, but did not differ from the control and combined treatment (canthaxanthin + lutein). The lutein supplementation (50 mg kg‐1) improved survival and promoted efficient carotenoid pigmentation on the skin of goldfish juveniles.     

Attachment and growth of vegetative propagules of Chondria crassicaulis Harvey (Ceramiales,Rhodophyta) under various culture conditions

The red alga Chondria crassicaulis has a wide‐ranging bioactive chemical composition and is used as a local foodstuff, representing a potentially new cultivar in Korea. The cultivation techniques were developed by examining the monthly changes in frond weight in a field population of C. crassicaulis from November 2016 to October 2017. For seedling production, temperature and irradiance effects on the attachment and growth of vegetative propagules of C. crassicaulis were evaluated. In addition, effects of day length and salinity on the propagule growth were examined. C. crassicaulis is a year‐round species with a maximum frond wet weight of 817 mg observed in July 2017, as seawater temperature increases to 20°C. The attachment of vegetative propagules was significantly affected by temperature and irradiance, with maximal values detected at 20–25°C and 60 µmol photons m^?2 s^?1. The relative growth rates of vegetative propagules of C. crassicaulis were the highest at 20–25°C, 60 µmol photons m^?2 s^?1, and a salinity of 25 psu. In conclusion, due to its tremendous tolerance under variable environmental conditions, the vegetative propagules of C. crassicaulis can be used as seedlings for mass cultivation.     

Effects of CO2 levels and light intensities on growth and amino acid contents in red seaweed Gracilaria lemaneiformis

The seaweed Gracilaria lemaneiformis is largely maricultivated in China, for use as food and as a material in the agar industry. This alga experiences ocean acidification caused by rising atmospheric CO₂ levels, and experiences changing light levels caused by self‐shading during the later period of mariculture. In this study, growth and amino acid (AA) content responses of G. lemaneiformis to different CO₂ levels (the present and the predicted increased levels) and varying light levels at 28 (±1)°C temperature conditions were investigated. The results showed that a higher light level enhanced algal growth and decreased water loss, but reduced AA accumulation. Decreased pH levels (as a result of CO₂ elevation) also enhanced algal growth and reduced AA contents, but the decreases in the AA score at the lower pH levels were not significant under the two light level treatments. In this study, the light treatments had greater influences on growth and AA contents than CO₂ levels. The results suggest that G. lemaneiformis quality will be negatively affected during the later mariculture production period as levels of CO₂ rise and global temperatures increase.     

饲料中添加龙须菜对眼斑拟石首鱼生长、脂肪酸组成、免疫及肠道的影响

为了研究添加龙须菜（Gracilaria lemaneiformis）对眼斑拟石首鱼（Sciaenops ocellatus）生长、脂肪酸组成、免疫和肠道的影响,在饲料中分别添加0（对照组）、1%、2%、3%、4%和5%的龙须菜,饲养初始体质量（9.380.06）g的眼斑拟石首鱼8周。结果表明,添加龙须菜对鱼体成活率、增重率（WG）和特定生长率（SGR）均不存在显著性影响（P0.05）,但1%~4%组的增重率均高于对照组,1%组的饲料效率和特定生长率最高;所有龙须菜添加组全鱼脂肪酸中的二十二碳六烯酸（DHA）均高于对照组,且添加量为5%时DHA显著高于对照组（P0.05）;肝脏中超氧化物歧化酶（SOD）活性在4%组显著高于对照组（P0.05）;3%组肠道粘膜褶最高且组织状况最好。由此可见,饲料中添加龙须菜对眼斑拟石首鱼生长有一定的促进作用,且添加适量龙须菜可以改善眼斑拟石首鱼的肝脏和肠道健康,提高全鱼DHA含量。     

Effect of dietary chitosan on growth performance,haematology, immune response,intestine morphology,intestine microbiota and disease resistance in gibel carp (Carassius auratus gibelio)

A 75‐day experiment was conducted with juvenile gibel carp (Carassius auratus gibelio) (4.80 ± 0.01 g) to evaluate effects of dietary chitosan on fish growth performance, haematology, intestine morphology and immune response. Six isonitrogenous (crude protein: 383 g kg^?1), isolipid (97.5 g kg^?1) and isocaloric (gross energy: 16.7 kJ g^?1) diets were formulated to contain 0, 1800, 4000, 7500, 10 000, 20 000 mg kg^?1 chitosan, respectively. The results showed that the growth was depressed when the fish fed with 10 000 mg kg^?1 chitosan. Serum cholesterol, triglyceride and low‐density lipoprotein decreased in 10 000 and 20 000 mg kg^?1 chitosan. On day 75, blood leucocyte phagocytic activity respiratory burst and alternative pathway of complement haemolytic activity were enhanced in 4000 mg kg^?1 chitosan. The number of goblet cell, intraepithelial lymphocyte of mid‐intestine and microvilli height of distal intestine increased at 4000 mg kg^?1 dietary chitosan. Dietary chitosan modulated intestine microbiota, depressed pathogen bacteria Aeromonas veronii‐like and improved Cellulomonas hominis‐like, Bacillus oceanisediminis‐like and two uncultured bacterium‐like species on day 75. Dietary 7500 and 10 000 mg kg^?1 chitosan enhanced the protection against Aeromonas hydrophila infection. In conclusion, oral administration of dietary 7500 mg kg^?1 chitosan for 75 days is recommended for the survival of gibel carp.     

Effects of supplementary fennel (Foeniculum vulgare) essential oil in diet on growth and reproductive performance of the ornamental fish,Convict cichlid (Cichlasoma nigrofasciatum)

This study evaluated the effects of diet containing 0 (C: control), 75 (D₁), 100 (D₂), 125 (D₃) and 150 (D₄) mg kg^?1 F. vulgare essential oil on growth and reproductive performance of C. nigrofasciatum. A total of 225 Convict cichlids female with mean weight (1.65 ± 0.02 g) were distributed into 15 glass aquaria (15 fish tank^?1) in triplicate treatments. During 40 days of experimental period, fish fed at 3% of their body weight daily. At the end of experiment, growth indices, gonadosomatic index and reproductive indices were determined. The best feed conversion ratio was obtained in D₄ (1.19 ± 0.03, P < 0.05). The addition of F. vulgare essential oil did not have any statistical effects on other growth indices (specific growth rate, weight gain and condition factor). Total survival rates in all treatments and control were uniformly high, ranging from 93% to 97% (P > 0.05). F. vulgare essential oil has no negative effect on survival rate of C. nigrofasciatum. There were no significant differences among protein content of fish body (P > 0.05). The lowest value of fat content (26.5 ± 0.5%) was observed in D_2, and it had significant difference with control and other groups (P < 0.05). The ash percentage in treatments fed with F. vulgare essential oil were higher than control fish (P < 0.05). The highest moisture content was detected in D₄ (72.68 ± 0.19%) and D₂ (71.23 ± 2%) groups. Among the used dosage, D₄ was the most effective dosage that could significantly increase GSI (11.06 ± 1.55%), fecundity (340 ± 21) and hatching ratio (92.33 ± 1.63%). There were no significant differences in diameter of eggs among various treatments (P > 0.05).     

Effect of stocking density on growth performance of juvenile sea cucumber Holothuria tubulosa (Gmelin, 1788)

Stock density is one among the most important factors in aquaculture that directly influences the growth of organisms; however, there is limited information about the effects of stocking density on growth performance of sea cucumber Holothuria tubulosa (Gmelin, 1788) that has a commercial potential and represents a new species for aquaculture. In this study, we investigated the effect of stocking densities on the growth performance of juvenile H. tubulosa (40.3 ± 3.34 g) in laboratory conditions. Stocking densities were selected as 6, 15 and 30 ind m^?2 with total biomass 253.3 ± 0.18, 601.2 ± 0.11 and 1201.4 ± 0.15 g m^?2 respectively. We monitored the growth by wet weights and calculated the growth performance through weight gain, growth rate, specific growth rate, relative weight gain, coefficients of variation and survival rate during 8 weeks of research period. We found that individual mean weight gain in 6 ind m^?2 group was approximately 29.53 g while it was 3.03 g and ?4.36 g for 15 ind and 30 ind m^?2 groups respectively. Results have shown that the specific growth rate tends to decrease as the number of individuals in unit area increases. The final mean weight, growth rate, specific growth rate, relative weight gain and coefficients of variation were significantly different among treatment groups. In conclusion, a density of 6 ind m^?2 is recommended for stocking juvenile H. tubulosa under rearing conditions. Stocking density of 15 ind m^?2 is not favourable for long term as the growth rate is negligible where 30 ind m^?2 should be avoided in tank‐based rearing units.     

Effect of temperature on growth,digestion and immunity of green,white and purple sea cucumbers,Apostichopus japonicus (Selenka)

Three color morphs (white, green and purple strains) of Apostichopus japonicus (Selenka) were cultured in artificial seawater, for approximately 90 days, in three temperature ranges: 27–22°C (high), 22–17°C (mid) and 17–12°C (low). All strains grew in all temperature ranges. Temperature significantly affected growth rate, digestibility, digestive enzymes and immune‐related enzymes. Highest specific growth rates were exhibited in 4‐month‐old sea cucumbers at mid and high temperatures, and in 16‐month‐old sea cucumbers at mid and low temperatures. Specific growth rates of green and purple strains were not significantly different, but were significantly higher than that of the white strain at mid temperatures. The digestibility of each strain was significantly higher at 27°C, 22°C and 17°C than at 12°C. Green‐strain digestibility was higher than that of purple and white strains at specific temperatures. Protease and amylase activities of all strains followed bell‐shaped temperature curves with maximum digestive enzyme activity at 17°C. The activities of alkaline and acid phosphatases were higher in the guts of the green strain than in the white or purple strains at the same temperature. Superoxide dismutase activity was higher in the purple strain than in white and green strains.     

Retracted: Effect of concentration of the microalga Dunaliella tertiolecta on survival and growth of fairy shrimp,Phallocryptus spinosa Milne Edwards, 1840 (Crustacea: Anostraca)

We investigated the effects of concentration of the microalga Dunaliella tertiolecta on the growth and survival of fairy shrimp, Phallocryptus spinosa. Newly hatched nauplii were stocked into containers, maintained at different concentrations of D. tertiolecta (at 18, 36, 54, 72 and 90 × 10⁶ cells mL^?1). All treatments were in quadruplicate and each replicate was stocked with 100 larvae in a 2‐L cylindrical bowl. We studied the survival and growth of the fairy shrimp after 3, 6, 9, 12 and 15 days of culture. The results indicated significant differences, in terms of growth and survival, of fairy shrimps fed at different algal densities. The highest and lowest growth and survival among the treatments were observed on Day 15, the highest in animals fed at a concentration of 90 × 10⁶ cells mL^?1 and the lowest in animals fed at a concentration of 18 × 10⁶ cells mL^?1. We conclude that the growth and survival of the P. spinosa increased with increasing density of algae, to a threshold level. Within certain concentration limits, the addition of D. tertiolecta substantially improved the performance of larval culture of P. spinosa, suggesting that this fairy shrimp has potential in terms of aquaculture development.     

Effect of dietary Clostridium butyricum and different feeding patterns on growth performance,antioxidant and immune capacity in freshwater prawn (Macrobrachium rosenbergii)

An 8‐week study was conducted to evaluate the effects of different feeding patterns with dietary Clostridium butyricum supplementation on growth performance, antioxidant and non‐specific immune responses in freshwater prawn, Macrobrachium rosenbergii (0.39 ± 0.001 g). There were four feeding methodologies: feeding basal diet continuously (P1); feeding diet with 500 mg/kg C. butyricum continuously (P2); feeding diet with 500 mg/kg C. butyricum 5 days after 2 days of basal diet (P3) and feeding diet with 500 mg/kg C. butyricum 2 days after 5 days of basal diet (P4). The results revealed that prawns in P3 had the highest weight gain rate (WGR) and lowest feed conversion ratio (FCR) than the other groups. Haemolymph total protein levels and superoxide dismutase activity increased significantly in P2, P3 and P4 groups, while malondialdehyde content and anti‐superoxide anion levels decreased significantly compared to control. The mRNA expression of intestinal dorsal and Toll in P2 and P3 groups decreased significantly compared to control. Prawns in P3 exhibited improved growth performance, increased antioxidant capacity and enhanced immune function. We concluded that feeding diet with 500 mg/kg C. butyricum for 5 days after 2 days of basal diet was recommended for M. rosenbergii.     

Effect of Lactobacillus acidophilussupplementation on growth performances,digestive enzyme activities and gut histomorphology of striped catfish (Pangasianodon hypophthalmusSauvage, 1878) juveniles

The influence of dietary supplementation of Lactobacillus acidophilus, on growth performance, digestive enzyme activities, gut histomorphology and gut microflora were evaluated in juveniles striped catfish (Pangasianodon hypophthalmus). Five experimental diets were formulated by supplementing 0, 10³, 10⁵, 10⁷ and 10⁹ CFU/g L. acidophilus in fishmeal and casein‐based semi‐purified diet. Triplicate groups of striped catfish (21.69 ± 0.18 g) were stocked in 15 fiberglass tanks with stocking density of 25 individuals per tank and fed twice daily at 2.5% of the fish body weight for 12 weeks. Weight gain, specific growth rate, feed conversion ratio and the protein efficiency ratio were significantly higher in fish fed with 10⁵ and 10⁷CFU/g L. acidophilussupplemented diets compared with the other treatment groups. Compared with the control and fish fed low (10³ CFU/g) L. acidophilus supplementation, those fed with 10⁵ and 10⁷ CFU/g had significantly higher (p < 0.05) apparent protein digestibility. Inclusion of L. acidophilus at 10⁷ CFU/g diet significantly increased amylase, protease and lipase activities. Microscopic analysis showed that the villi length in both the anterior and posterior gut and microvilli length in the posterior gut increased significantly in fish fed L. acidophilus supplementation at 10⁵ and 10⁷ CFU/g of diet. The fish fed L. acidophilus supplemented diets significantly increased the total lactic acid bacteria counts in the gut of striped catfish compared with the control‐fed group. Based on gut histomorphology and growth performance, inclusion of L. acidophilus at 10⁵ CFU/g appears to have the most positive effect on striped catfish farming.     

Effect of Ocimum sanctum Linn. (Tulsi) extract on the immunity and survival of Labeo rohita (Hamilton) infected with Aeromonas hydrophila

A 60 days study was conducted to evaluate the efficacy of water extract of Ocimum sanctum Linn. leaf on the immune response and disease resistance of Labeo rohita fingerlings against the Aeromonas hydrophila infection. Ocimum sanctum extract was incorporated in the diets (at 0.0%, 0.05%, 0.1%, 0.2%, 0.5% and 1%) of Labeo rohita, rohu fingerlings (6.6 ± 0.013 g). After 42 days blood, plasma and serum were sampled to determine super oxide anion production, lysozyme activity, total immunoglobulin in plasma, blood glucose, serum total protein, albumin, globulin, albumin:globulin ratio, WBC, RBC, haemoglobin content. Fish were challenged with A. hydrophila after 42 days and mortalities were recorded over 18 days post infection. The results demonstrate enhanced super oxide anion production, lysozyme activity, total immunoglobulin in plasma, serum total protein, globulin, total RBC counts, total WBC counts and haemoglobin content (P < 0.05) in treatments group compared with control group. Dietary O. sanctum extracts of 0.2% showed significantly (P < 0.05) higher protection relative percentage survival (RPS 40.00 ± 5.773%) against A. hydrophila infection than control. These results indicate that O. sanctum leaf extract stimulates the immunity and makes L. rohita more resistant to bacterial infection (A. hydrophila).     

The effect of insect meal as a feed ingredient on survival,growth, and metabolic and antioxidant response of juvenile prawn Palaemon adspersus (Rathke, 1837)

For successful prawn aquaculture, feeds should be based on readily consumed ingredients that promote survival and optimal growth performance. This pilot study investigates the rearing of juvenile Baltic prawn Palaemon adspersus. Two feeding trials were carried out for 60 days; both incorporated insect meals, the first one in fishmeal‐based diets, whereas the second one in plant meal ones. Insect meals derived from larvae of Tenebrio molitor (TM), Hermetia illucens (HI) and Musca domestica (MD) were tested as feed ingredients. This study indicated that the inclusion of HI in fishmeal diets resulted in significantly higher growth performance and survival of the prawns, whereas the MD diet led to similarly high growth performance reducing significantly their survival. Growth performance was not affected by the insect inclusion in the plant‐based diets, but survival was higher in the TM and HI inclusion diets. The inclusion of TM and HI resulted in higher protein and energy content of the prawns’ muscle when incorporated in fishmeal and plant meal diets respectively. No significant differences were observed in the activities of hepatopancreas’ amino acid‐catabolizing enzymes. Concluding, the combinations fishmeal–HI and plant meal–TM can be used for the successful rearing of Baltic prawn.