Effects of probiotic Pediococcus acidilactici on growth performance,survival rate,and stress resistance of Persian sturgeon (Acipenser persicus)

This study was conducted to examine the effect of Artemia urmiana nauplii enriched with Pediococcus acidilactici on growth performances, survival rate, and stress resistance of Persian sturgeon (Acipenser persicus). Artemia nauplii were enriched with P. acidilactici at concentration of 10¹⁰ CFU/ml for 3 h (T3), 6 h (T6), 9 h (T9), and one nonenriched nauplii treatment (control). Since nauplii enriched for 9 h had the most significant CFU/g, fish were fed with T9 for 11 days and compared with the control. To evaluate the effect of probiotic on fish resistance, Persian sturgeon larvae were subjected to osmotic shocks of 15, 25, or 35 ppt; four pH treatments, pH 5, pH 6, pH 8 or pH = 9; and air for 5, 10, 15, or 20 s on the 11th day. There were no significant differences in final weight, weight gain, CF, SGR, and FCR between T9 and control (P > 0.05). However, the survival rate of larvae fed nauplii enriched for 9 h increased significantly in comparison with the control group (P < 0.05). In addition, significant higher resistance to all stress challenges was observed in the T9 group.     

Mass culture of fairy shrimp Streptocephalus proboscideus (Crustacea – Anostraca) and its use in larviculture of the Persian sturgeon, Acipenser persicus

This study was conducted with cysts of Streptocephalus proboscideus obtained from the University of Gent‐Belgium. The cysts were hatched in Environmental Protection Agency (EPA) medium. The nauplii were reared at the Sturgeon Research Institute using a pure culture of Scenedesmus obliquus alga supplied at a density of 5 × 10³ cell mL⁻¹ that gradually increased to 1 × 10⁴, 5 × 10⁴ and 1 × 10⁵ cell mL⁻¹ with the growth of the nauplii. The nauplii attained sexual maturity and started producing cysts in 8 days and yielded a mean cyst number of 220±40 female⁻¹ brood⁻¹ cysts. These cysts were used in the larviculture of Persian sturgeon, Acipenser persicus (Borodin). Forty‐three larvae of Persian sturgeon (mean weight: 15.4±1.1 mg; mean length: 27.1±2.7 mm) with roughly absorbed yolk sacs were stocked in three aquaria and fed S. proboscideus nauplii at 8‐h intervals. By the end of the experiment (day 5), the mean weight and length of Persian sturgeon larvae were 51.4±13.3 mg and 20.7±1.4 mm respectively.     

The effects of dietary probiotic Bacilli (Bacillus subtilis and Bacillus licheniformis) on growth performance,feed efficiency,body composition and immune parameters of whiteleg shrimp (Litopenaeus vannamei) postlarvae

The present study investigates the effects of dietary commercial Bacilli probiotic (Bacillus subtilis and Bacillus licheniformis) on the growth performance, feed efficiency, body composition and immune parameters of Litopenaeus vannamei. The L. vannamei postlarvae were supplied and acclimated (in 500‐L tanks) to laboratory conditions for 14 days. The shrimps were fed with diets containing 1 × 10⁴ and 1 × 10⁸ CFU/g probiotic Bacilli for 60 days. At the end of the feeding trial, growth performance parameters, body composition, serum biochemical parameters and the hemocytes count were evaluated. Shrimps fed diets supplemented with 1 × 10⁴ and 1 × 10⁸ CFU/g probiotic Bacilli showed improved weight gain, total length, specific growth rate, FCR and survival compared with the control group. The body composition studies revealed higher dry matter, crude protein and ash in shrimps fed with 1 × 10⁴ and 1 × 10⁸ CFU/g probiotic Bacilli. Also, dietary administration of 1 × 10⁴ and 1 × 10⁸ CFU/g probiotic Bacilli decreased serum glucose and cortisol levels. However, significantly increased total protein, lysozyme and hemocyte cell count were noticed in shrimps fed 1 × 10⁴ and 1 × 10⁸ CFU/g probiotic Bacilli. In general, the findings of this study proved that oral administration of 1 × 10⁴ and 1 × 10⁸ CFU/g commercial probiotic Bacilli improved growth performance, feed utilization and immune parameters in whiteleg shrimp (Litopenaeus vannamei).     

Effects of dietary Lactobacillus delbrueckii on growth performance,body composition,digestive and absorptive capacity,and gene expression of common carp (Cyprinus carpio Huanghe var)

The present study aimed to investigate the effects of dietary supplementation of Lactobacillus delbrueckii (L. delbrueckii) on growth performance, body composition, intestinal enzyme activities and gene expression of Cyprinus carpio Huanghe var. Fish (mean 1.05 ± 0.03 g in triplicate) were conducted for 8 weeks with five treatments in triplicate. The fish in the control were fed a basal diet, and those in D2, D3, D4 and D5 were fed basal diet containing L. delbrueckii at 1 × 10 CFU/g, 1 × 10 CFU/g, 1 × 10 CFU/g and 1 × 10 CFU/g. The growth performance and the hepatic IGF‐I expression of fish increased significantly as L. delbrueckii level increased from 0 to 1 × 10 CFU/g, but decreased significantly with further increasing L. delbrueckii levels. The whole body protein, lipid contents, intestinal digestive and absorptive enzyme activities were significantly affected by dietary L. delbrueckii levels with the highest values observed in fish fed diet containing 1 × 10⁶ CFU/g L. delbrueckii. The carbohydrate content showed the opposite trend. The results suggest that supplementation of L. delbrueckii as probiotic in the diet at approximately 1 × 10 CFU/g can improve growth performance, intestinal enzyme activities and the growth‐related gene expression in Cyprinus carpio Huanghe var.     

Effects of dietary Bacillus pumilus on growth performance,innate immunity and digestive enzymes of giant freshwater prawns (Macrobrachium rosenbergii)

The present study was conducted to investigate the effects of Bacillus pumilus on the growth performance, innate immunity and digestive enzymes of the giant freshwater prawn, Macrobrachium rosenbergii. Prawns (mean weight: 1.81 ± 0.01 g) were fed different levels of B. pumilus at doses of 0, 1 × 10⁷, 1 × 10⁸ and 1 × 10⁹ CFU/g to produce one control group and three experimental groups (G1, G2 and G3), respectively. After a 60‐day experimental feeding period, the results showed that the final weight, weight gain rate (WGR) and specific growth rate (SGR) were significantly higher in experimental groups than in the control (p < 0.05), whereas these improvements did not differ significantly (p > 0.05) among experimental groups. The improvements in phagocytic activity, respiratory burst (RBs) activity and the activity of catalase (CAT), nitric oxide synthase (NOS) and acid phosphatase (ACP) were significantly higher in G2 and G3 than in the control and G1 (p < 0.05). Further, the activity of CAT, NOS and ACP significantly increased with an increase in the dietary level of B. pumilus (p < 0.05). The activity of phenoloxidase (PO) in G3 was significantly higher than that in the control (p < 0.05). The activity of amylase was significantly higher in the groups G2 and G3 than that in the control group. G3 improved the activity of protease compared with the control (p < 0.05). In conclusion, the results of this study indicated that the potential use of B. pumilusat a dose of 1 × 10⁸ CFU/g feed could improve the growth, immunity and digestive enzymes of M. rosenbergii.     

The administration of Lactobacillus plantarum directly to food: An effective way to improve the survival and growth of juvenile lined seahorses (Hippocampus erectus)

Previously, we found Lactobacillus plantarum had probiotic effects on lined seahorse (Hippocampus erectus) juveniles by the addition Lactobacillus directly into rearing seawater containing juveniles and their food (i.e. copepods). However, how the juveniles consumed Lactobacillus, directly from water or from copepods in whose guts Lactobacillus may have accumulated by ingestion, is still unclear. To clarify this, three experiments were successively carried out in this study. In the first experiment, the manner by which juveniles consumed Lactobacillus, namely, directly from food, was discovered via a 2 × 2 factorial design with two factors of water and food, and two levels with and without L. plantarum. In the second experiment, a 5 × 4 factorial design with five levels of L. plantarum doses (D: 5, 10, 20, 40 and 80 × 10⁸ cfu/L) and four levels of enrichment time (T: 0.5, 1.0, 1.5 and 2.0 hr) was conducted to analyse lactic acid bacteria (LAB) contents in the enriched copepods under different treatments. In the third experiment, six kinds of Lactobacillus‐enriched copepods chosen from the second experiment that carried significantly different LAB contents were fed to juveniles, and it was found that the copepods containing LAB greater than 5 log₁₀colonies/g had the most improved effects for survival and growth. In conclusion, the effective manner of L. plantarum administration in seahorses is by the addition to their food. Additionally, D40 * T1.0, whose LAB content was more than 5 log₁₀colonies/g, is generally the most economic copepod treatment for improving survival and growth in H. erectus rearing.     

Minimally invasive surgical technique for egg collection from the Persian sturgeon, Acipenser persicus

A minimally invasive surgical technique (MIST) for the removal of ovulated eggs from Persian sturgeon Acipenser persicus was tested on broodstocks caught from the wild to determine whether it affected fecundity or hatching rates compared with the traditional stripping method of killing and removing the eggs (commonly used in hatchery). Morphological parameters of females, germinal vesicle (GV) position, weight of obtained egg, number of eggs/gram, fertilization rate, and percentage of hatching during incubation were not significantly different between the MIST and traditional stripping methods. Obtained ova were 4.8 ± 0.4 kg female⁻¹ in the MIST and 4.6 ± 0.5 kg female⁻¹ in traditional stripped groups, respectively; the fertilization rate was 83.4 ± 11.2% and 80.0 ± 7.2% in groups, respectively. The results of this study showed that the minimally invasive surgical technique approach is efficient, practical, and less stressful to Persian sturgeon broodstocks during artificial propagation than other reported egg collection procedures.     

Influence of Stocking Density on Growth and Physiological Responses of Beluga,Huso huso (Brandt, 1869), and Ship Sturgeon,Acipenser nudiventris (Lovetsky, 1828), Juveniles in a Flow‐through System

The influence of three different initial stocking densities (low stocking density [LSD] = 1.5 kg/m²; medium stocking density [MSD] = 3 kg/m²; and high stocking density [HSD] = 6 kg/m²) in flow‐through systems was evaluated on growth and welfare in beluga, Huso huso, and ship sturgeon, Acipenser nudiventris, juveniles for 2 mo. Fish were kept in 18 concrete square tanks (2.0 × 1.0 × 1.2 m³) at 22.3 ± 0.4 C and under a natural photoperiod. In both species, the growth performance in terms of final body weight, weight gain, specific growth rate, and feed intake significantly decreased with increasing stocking density (P < 0.05). In both species, the percent of neutrophils increased after 60 d of trial (P < 0.05). Moreover, hematocrit and white blood cell counts increased after 60 d of trial in ship sturgeon (P < 0.05). Plasma immunoglobulin significantly decreased with increasing stocking density in both species. Plasma insulin‐like growth factor I decreased with increasing stocking density in beluga; however, it was not affected in ship sturgeon. Overall, these results showed that the LSD group in both species demonstrated more homogeneous and higher growth rate than the MSD and HSD groups.     

Effects of dietary mono‐ and multiprobiotic strains on growth performance,gut bacteria and body composition of Javanese carp (Puntius gonionotus,Bleeker 1850)

This study investigated the effects of dietary mono‐ and multiprobiotic strains of Enterococcus faecalis, Lactobacillus fermentum and Leuconostoc mesenteroides on growth performance, intestinal bacteria and body composition of Javanese carp (Puntius gonionotus). Moreover, the effect of storage temperature on lactic acid bacteria (LAB) viability in the feed was studied. Compared to the control group, significant (P < 0.05) effect on weight gain, feed conversion ratio, specific growth rate and protein efficiency ratio of probiotic fed Javanese carp was observed. Inclusion of individual LAB strains in the diet resulted in significantly improved growth performances of Javanese carps compared to fish fed a diet supplemented LAB mixture. The inclusion level of E. faecalis at 10⁷ colony‐forming unit (cfu) g⁻¹ in the diet revealed higher growth performance compared to other treatments. The population levels of LAB in the fish intestine were significantly increased while the levels of Gram‐negative bacteria were significantly decreased compared to the control. No significant variations were observed in the chemical composition of the carcass by probiotics. The viability of LAB in feed was higher when stored at 4 °C compared to 25 °C. It is suggested that E. faecalis has a greater potential for use in improving Javanese carp culture outcomes.     

The effects of oligofructose on growth performance,survival and autochthonous intestinal microbiota of beluga (Huso huso) juveniles

Preliminary experiments were undertaken to investigate the effects of oligofructose on beluga sturgeon (Huso huso) growth performance, survival and culturable autochthonous intestinal microbiota. Juveniles (20 g) were fed diets containing varying levels of oligofructose (10, 20 and 30 g kg^?1) at 2–3% body weight per day for 7 weeks. Compared to the control group, no significant (P > 0.05) effect on growth performance was observed in fish fed diets supplemented with oligofructose at 10 and 20 g kg^?1. However, compared to the 20 g kg^?1 group, feeding oligofructose at 30 g kg^?1 resulted in adverse effects on growth performance. Dietary supplementation of oligofructose at 20 g kg^?1 significantly increased survival rate. Microbiological assessment indicated that the viable culturable autochthonous levels were not affected by dietary oligofructose. Although lactic acid bacteria (LAB) were not a dominant component of the endogenous autochthonous microbiota, LAB levels were significantly elevated in fish fed 20 g kg^?1 dietary oligofructose. This elevated LAB population was able to persist for at least 1 week after reverting the prebiotic group back to a control diet. This study encourages further research on different aspects of oligofructose in sturgeon culture with clear emphasis on optimizing dosage levels.     

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.     

A comparative study of some hematological features in young reared sturgeons (Acipenser persicus and Huso huso)

The physiological condition in fishes required for their selection as broodfish can be determined by hematological studies. The present study aims at examining the hematological indices in juvenile sturgeons at different stages of growth. The main blood features, such as total albumin content in blood, hemoglobin concentration and the erythrocyte and leukocyte count, were measured in a total of 54 specimens of 1-, 2- and 6-year old sturgeon (Persian sturgeon Acipenser persicus and beluga Huso huso), artificially produced at the Shahid Dr. Beheshti Fish Breeding and Rearing Center located in the Gilan Province.In the Persian sturgeon specimens studied, the total albumin concentration in the blood increased from 26.05 to 52.50 g l^–1, the hemoglobin concentration increased from 42.2 to 65.8 g l^–1, the erythrocyte count increased from 240 to 452.5 thousand cell ml^–1 and the leukocyte count increased from 13.43 to 46.48 thousand cells ml^–1. The total leukocyte was composed of 73.25 to 82.70% lymphocytes, 12.3 to 20% neutrophils, 2.25 to 6.50% eosinophils and 0.2 to 2.5% monocytes.In the beluga specimens studied, the total albumin concentration in the blood increased from 20.05 to 42.20 g l^–1, the hemoglobin concentration increased from 46.3 to 78.6 g l^–1, the erythrocyte count increased from 495 to 735 thousand cells ml^–1 and the leukocyte count increased from 31.6 to 57.7 thousand cells ml^–1. The total leukocyte was composed of 54.5 to 67.5% lymphocytes, 22.63 to 33.86% neutrophils, 6.60 to 13.7% eosinophils and 0.6 to 2.25% monocytes.This research reveals the trends of some hematological features during the growth and development of sturgeons in the South Caspian Sea, reared in artificial conditions. It shows that with the increase in age, the hematological indices also increased.     

Soya bean‐based diets plus probiotics improve the profile of fatty acids,digestibility, intestinal microflora,growth performance and the innate immunity of beluga (Huso huso)

This study was conducted to investigate the effect of different methods of using probiotics Bacillus subtilis and Bacillus licheniformis in soya bean‐based diets on the physiology of beluga (Huso huso) (351 ± 4 g). Five experimental diets were formulated to feed beluga for 10 weeks. The results showed that there was no significant difference in weight gain between control (446 g) and 70%SBM‐SPRAY2 (409 g) treatments. Long‐chain polyunsaturated fatty acids in the muscle of beluga fed control (203.2 g/kg) and 70%SBM‐SPRAY2 (166.4 g/kg) diet did not change statistically. Blood performance as a newly introduced factor in individuals fed dietary control (64.06) and 70%SBM‐SPRAY2 (64.33) had higher value as compared with those fed dietary 70%SBM‐DIET2 (61.90) (p < 0.05). Also, total protein (1.68 g/dl) and RBC (0.74 × 10⁶/mm³) in fish fed 70%SBM were statistically lower than other treatments (p < 0.05). Lysozyme, alternative complement activity and total viable counts in beluga fed dietary probiotics were significantly higher than others. In conclusion, feeding fish with the 70%SBM‐SPRAY2 diet improved fish growth and health.     

Effects of an Enterococcus faecium‐based probiotic on growth performance and health of Pirarucu,Arapaima gigas

Intensive fish farming has resulted in an increased concern for disease outbreaks. Probiotic use is one of the strategies being developed to improve fish health and productivity. Measures of probiotic colonization, growth performance, haematological characteristics and parasite load were used to evaluate the effect of diets supplemented with Enterococcus faecium on growth and health of Arapaima gigas juveniles. A completely randomized design with four treatments (diet with E. faecium at 1 × 10⁶ CFU/g and 1 × 10⁸ CFU/g, control diet and diet with the culture medium MRS) and three replicates was used. Ninety‐six Arapaima juveniles were distributed in 12 cages fed with the specified diet for 68 days. Colonization of the intestinal tract by lactic acid bacteria reduced the total number of heterotrophic bacteria in fish fed with probiotics compared to controls. Fish fed a supplemented diet containing 1 × 10⁸ CFU/g presented higher values of weight gain, survival and fish growth uniformity, and lower values of feed conversion ratio. The prevalence of Trichodina sp. could have affected the survival of fish in the control group. Reduction in parasite load and an increase in haematocrit, the number of erythrocytes, thrombocytes, neutrophils and monocytes were also observed in fish fed the diet containing 1 × 10⁸ CFU/g. Enterococcus faecium presented a probiotic effect in A. gigas juveniles and can be recommended for use at a concentration of 1 × 10⁸ CFU/g to modify the gut microbiota, improve growth performance and haematology and reduce parasitic load.     

Tuna viscera protein hydrolysate: nutritive and disease resistance properties for Persian sturgeon (Acipenser persicus L.) larvae

The effect of fish protein hydrolysate (FPH) on the growth, feed utilization, digestive enzymes, gut microflora and resistance to bacterial challenge in Persian sturgeon (Acipenser persicus) larvae during a 45‐day feeding trial has been investigated. Artificial diets containing different levels of tuna visceral protein hydrolysate (PH0, PH10, PH25 and PH50) and live foods (Artemia: 5 days, Daphnia: 40 days) were fed to Persian sturgeon larvae. Larvae fed on the PH10 and PH25 had growth, feed utilization, protein content and trypsin activity significantly better than PH0 and PH50 groups (P < 0.05). Condition factors, survival rate and pepsin activity were not significantly different (P > 0.05). Brush border membrane enzymes to cytosolic enzyme ratio revealed that maturation had been occurred in 41 days post hatch (dph) at moderate FPH levels. In 54 dph larvae, this ratio was not affected by the level of FPH in the diet. No significant differences were observed in the total number of gut microflora or in the resistance to Aeromonas hydrophila (P > 0.05), whereas lactic acid bacteria was significantly higher in PH50 (P < 0.05). The results of this study show that application of moderate levels of FPH in Persian sturgeon diets could enhance larvae performance due to the early maturation in intestinal.     

Dietary supplementation of probiotics and influence on feed efficiency,growth parameters and reproductive performance in female rainbow trout (Oncorhynchus mykiss) broodstock

The aim of this study was to determine the effects of dietary probiotics on reproductive performance, growth, haematological and biochemical parameters of female rainbow trout broodstock. A total of 60 broodstocks with an average initial weight of 2,267.4 ± 54.9 g were divided into four groups and three replicates in raceway ponds. Fish were fed with diets containing 0 (control), 1 × 10⁹ (P1), 2 × 10⁹ (P2) and 4 × 10⁹ (P3) CFU probiotic per kg diet twice a day for 8 weeks before spawning season. Results revealed that higher levels of dietary probiotics (P3) enhanced protein efficiency ratio and decreased feed conversion ratio (p < .05). There were no significant differences in haematological and other growth parameters among different treatments. According to the results, probiotic‐fed treatments had the lowest levels of cholesterol (237.7 ± 4.3 mg/dl) and the highest levels of total protein (11.3 ± 0.3 g/dl) and albumin (6.9 ± 0.3 g/dl), so that differences were found between P3 and control groups in all cases (p < .05). Based on the observations from reproductive parameters, the highest egg diameter, working and relative fecundities, fertilization and hatching rates, eyed eggs survival and alevins survival rates up to the absorption of the yolk sac were observed in P3 treatment (p < .05). Moreover, eyeing, hatching and yolk sac absorbing stages in P3 treatment were earlier than those in other treatments (p < .05). The results of present study demonstrated that probiotic supplementation improved reproductive performance and some growth and biochemical parameters in female rainbow trout broodstock and the best performance was observed in fish fed 4 × 10⁹ CFU probiotic per kg diet. Due to an increase in egg production and egg size in probiotic‐fed treatments, this feed additive can be used as a suitable ingredient to increase high‐quality egg production in rainbow trout breeders.     

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.     

Dietary supplementation with autochthonous Bacillus cereus improves growth performance and survival in tambaqui Colossoma macropomum

The aim of this study was to evaluate the effect of dietary supplementation with the autochthonous probiotic bacteria Bacillus cereus on growth performance, haematological parameters and survival of tambaqui (Colossoma macropomum). Tambaqui fingerlings (0.94 ± 0.02 g) were fed for 120 days the following diets: basal (without probiotic) and three supplemented diets (4.2 × 10⁴, 3.9 × 10⁶ and 3.3 × 10⁸ CFU/g). Growth performance and haematological parameters were evaluated every 30 days. Thereafter, fish were challenged against Aeromonas hydrophila and survival was evaluated. Probiotic B. cereus improved weight and length gains (p < 0.05), and increased neutrophils and thrombocyte counts (p < 0.05) in tambaqui supplemented with 3.9 × 10⁶ CFU/g diet. Challenged fish fed unsupplemented diet presented the lowest survival rate (33.4%) while fish fed diets supplemented at 4.2 × 10⁴, 3.9 × 10⁶ and 3.3 × 10⁸ CFU/g B. cereus had 88.8%, 80.5% and 80.5% relative per cent survival respectively. These results demonstrated that B. cereus supplemented as probiotics to C. macropomum for 120 days improved physiological and haematological responses, leading to enhanced survival in this fish species.     

Dietary supplementation effects of Pediococcus acidilactici as probiotic on growth performance,digestive enzyme activities and immunity response in zebrafish (Danio rerio)

This study was carried out to assess the effects of Pediococcus acidilactici on zebrafish (Danio rerio). Different levels of P. acidilactici including 0, 1 × 10⁶, 2 × 10⁶, 4 × 10⁶ and 8 × 10⁶ colony‐forming unit per g of the diet (cfug^?1) were examined in fish with 120 ± 10 mg weight for 60 days in a completely randomized design. The results showed that the best growth indices were recorded in group 4 × 10⁶ cfug^?1 (p < 0.05). The highest number of total viable count and lactic acid bacteria of intestine were found in group 4 × 10⁶ cfug^?1 (p < 0.05). The maximum activity of digestive enzymes including amylase, lipase, protease and alkaline phosphatase was observed in group 4 × 10⁶ cfug^?1. The highest activity for superoxide dismutase was recorded in group 4 × 10⁶ cfug^?1 while catalase, glutathione peroxidase and glutathione reductase showed the highest activity in group 8 × 10⁶ cfug^?1. The most growth inhibition zone of Aeromonas hydrophylla, Flavobacterium columnare, Vibrio anguillarum and Edwardsiella tarda was found in group 4 × 10⁶ cfug^‐1 (p < 0.05). Therefore, P. acidilactici as a probiotic improved growth and immunity of the zebrafish and could be used by zebrafish farmers.     

Growth performance,nutrient digestibility and digestive enzyme activity in Asian seabass,Lates calcarifer juveniles fed diets supplemented with cellulolytic and amylolytic gut bacteria isolated from brackishwater fish

Asian seabass, Lates calcarifer juveniles were fed for 30 days to evaluate the efficacy of cellulolytic (Bacillus sp. DDKRC1.) and amylolytic (Bacillus subtilis DDKRC5.) bacteria supplemented diets. Four experimental groups were maintained in triplicate of which group I was the control group and received no bacterial supplementation. Groups II, III and IV were fed diet supplemented with B. subtilis DDKRC5. (14.25 × 10⁷ CFU/mL), Bacillus sp. DDKRC1. (2.94 × 10⁷ CFU/mL) and mixture of both the microbes (1:1 ratio), respectively, @ 1% (v/w). After 30 days of feeding, fish reared as group IV showed significantly higher (P < 0.01) weight gain (141.42%), survival (91.50%), protein efficiency ratio (1.18) and significantly lower (P < 0.01) FCR (2.15) than that of other groups. Nutrient digestibility parameters were significantly (P < 0.01) higher in group IV followed by groups III, II and I. Digestive cellulase, amylase and protease activities in the gastrointestinal tract were also significantly (P < 0.01) higher in group IV. Amylolytic and cellulolytic microbial count in the gastrointestinal (GI) tract were significantly (P < 0.01) higher in groups II, III and IV as compared with that of control. It can be concluded that feed supplemented with mixture of B. subtilis DDKRC5. and Bacillus sp. DDKRC1. showed better performance in Asian seabass juveniles.