Effect of dietary graded levels of cottonseed meal and gossypol on growth performance,body composition and health aspects of allogynogenetic silver crucian carp,Carassius auratus gibelio♀ × Cyprinus carpio♂

A 6‐month trial was conducted to evaluate the effects of dietary cottonseed meal (CSM) and free gossypol (FG) on allogynogenetic silver crucian carp, Carassius auratus gibelio♀ × Cyprinus carpio♂ with 4 replicates of each treatment. Isonitrogenous and isocaloric diets were formulated with the 0 g kg^?1 (control), 200 g kg^?1, 400 g kg^?1, and 560 g kg^?1 CSM. Diets with FG were made by supplementing batches of control diet with 214 mg kg^?1, 428 mg kg^?1, and 642 mg kg^?1. Weight gain, specific growth rate, and protein efficiency ratio increased significantly up to an inclusion level of CSM of 400 g kg^?1 in the diet, with a significant decrease in food conversion ratio. Further increase in CSM to 560 g kg^?1 did not cause further changes in fish performance. Free gossypol did not affect fish performance significantly at any inclusion level. Neither CSM nor FG caused significant effects in any of the other evaluated parameters such as whole body composition, haemoglobin concentration, activities of serum lysozyme, superoxide dismutase, alanine aminotransferase and aspartate aminotransferase, and histology of hepatic tissues and midgut. Our results suggested that crucian carp can tolerate at least 642 mg kg^?1 FG and that it is safe to including 400 g kg^?1 CSM in crucian carp feed.     

Effects of glycinin on growth performance,immunity and antioxidant capacity in juvenile golden crucian carp,Cyprinus carpio × Carassius auratus

This study was designed to examine the effects of glycinin on growth, digestive ability, immune responses, antioxidant capacity and gene expression levels of golden crucian carp. Golden crucian carp were fed diets containing glycinin at 0, 30, 60, 90 and 120 g/kg, respectively, for 8 weeks. Body weight, weight gain percentage, specific growth rate and feed efficiency ratio were negatively related to the content of glycinin in diet. Activities of protease, acid phosphatase, alkaline phosphatase, lysozyme in hepatopancreas, and activities of catalase, glutathione peroxidase, superoxide dismutase, and total antioxidant capacity in the proximal intestine, mid intestine, distal intestine and hepatopancreas were negatively related to the content of glycinin in diet, whereas malondialdehyde in proximal intestine, mid intestine, distal intestine and hepatopancreas increased directly with the content of glycinin in diet. Furthermore, the relative expressions of TNF‐α and IL‐1β in proximal intestine, mid intestine and distal intestine increased directly with the content of glycinin in diet, whereas the relative expressions of TNF‐α and IL‐1β in hepatopancreas were negatively related to the content of glycinin in diets. The relative expressions of IL‐10 in proximal intestine, mid intestine, distal intestine and hepatopancreas all were negatively related to the content of glycinin in diets. In conclusion, reductions in growth, immunity and antioxidant capacity, intestine inflammation with dysfunction of digestive system occurred in golden crucian carp that fed a diet containing glycinin at 30 g/kg or higher after 8 weeks.     

Effects of totally replacing dietary fish oil by linseed oil or soybean oil on juvenile hybrid sturgeon,Acipenser baeri Brandt♀×A. schrenckii Brandt♂

The growth performance, body composition, fillet fatty acid content, serum hepatic enzymes and postprandial changes in serum lipid metabolism of hybrid sturgeon (70.8 ± 0.5 g) were investigated to determine the effects of total replacement of 80 g kg^‐1 fish oil (diet A) with linseed oil (diet B) and soybean oil (diet C), respectively. No significant differences in weight gain rate and specific growth ratio were observed among all fish groups (p > .05). Diet A fish group had the highest, but diet B fish group had the lowest feed intake (p < .05). Feed efficiency of fish fed diet A was significantly lower than the other two fish groups (p < .05). Fish fed diet A had the lowest fillet and liver lipid contents (p < .05). Serum lactate dehydrogenase, alanine aminotransferase and aspartate aminotransferase activities of fish fed diet A were significantly lower than those of fish fed diets B and C (p < .05). The contents of linoleic acid (C18:2n6) and linolenic acid (C18:3n3) in fillets showed a significantly positive linear correlation with the diets. Serum glucose and non‐esterified fatty acid were just affected by the time point (p < .05). The lipid source, time point and interaction of both factors had significant effects on serum triglyceride, high‐density lipoprotein cholesterol and low‐density lipoprotein cholesterol (p < .05). Serum total cholesterol was only affected by interaction of time point and lipid source (p < .05), and ketone body was not affected by lipid source, time point or interaction of both factors (p > .05). In summary, total replacement of fish oil with linseed oil or soybean oil had no significant adverse effects on hybrid sturgeon growth during 84‐day period, and linoleic acid and linolenic acid in fillet were modified by dietary treatments.     

高碳水化合物水平日粮对异育银鲫生长、生理、免疫和肝脏超微结构的影响

为了探讨异育银鲫对日粮中高碳水化合物的利用,选用168尾异育银鲫,分成2组,一组为正常对照组,投喂35%碳水化合物(35%CHO)水平日粮;另一组为高糖试验组,投喂50%碳水化合物(50%CHO)水平日粮每组设3个重复。在控温的循环水系统中饲养10周后,测定鱼体生长指标、肌肉成分、肝糖元、血液生化指标和免疫指标。结果表明,高糖组(50%CHO)显著(P<0.05)降低了特定生长率、增重率,但是对饵料系数、肝体比、脏体比、鱼体肌肉成分等没有显著(P>0.05)影响;两组异育银鲫血浆总蛋白、甘油三酯、总胆固醇、血糖和肝糖原含量都没有显著差异(P>0.05);高糖组(50%CHO)肝脏丙二醛含量显著升高(P<0.05)、天门冬氨酸转氨酶显著降低(P<0.05),而肝脏超氧化物歧化酶、总抗氧化能力、丙氨酸转氨酶和碱性磷酸酶都没有显著变化(P>0.05)。试验还对两组异育银鲫肝细胞进行超微结构观察,发现高糖饲料引起了异育银鲫肝细胞中糖原和脂肪的沉积,并对细胞和细胞器的结构产生一定损伤。从本试验结果来看,异育银鲫可以耐受50%饲料糖含量,但是长期摄食50%碳水化合物日粮对其生长不利,并会引起一定程度肝脏功能和结构的损伤。     

Effects of rhythmic temperature change on the growth,body composition and energy budget of hybrid grouper (Epinephelus lanceolatus♂ × Epinephelus fuscoguttatus♀)

Effects of rhythmic temperature change on the growth, body composition and energy budget of hybrid grouper (Epinephelus lanceolatus ♂ × E. fuscoguttatus ♀) were investigated. Nine groups of fish received repeating cycles of low‐temperature manipulation (22°C) for 1, 2 and 4 days followed by recovery temperature (28°C) for (3, 7 and 11 days), (6, 14 and 22 days) and (12, 28 and 44 days) respectively, designated as L1R3, L1R7, L1R11, L2R6, L2R14, L2R22, L4R12, L4R28 and L4R44 respectively. In the control group (C), fish were reared at 28°C throughout the whole experiment. After 96‐day feeding trail, the final weight, relative weight gain rate, specific growth rate, food conversion efficiency and apparent digestibility coefficient of fish in L4R28 were significantly higher than those of control (p < .05). The crude protein contents of fish in L2R14, L2R22, L4R12, L4R28 and L4R44 were significantly higher compared to the control (p < .05). According to energy budget, fish in L4R28 exhibited significantly higher proportion of food energy assimilated into growth and lower proportion consumed for excretion than the control fish (p < .05). These results indicated the occurrence of complete or over growth compensation in hybrid grouper, and the use of repeated cycles of low temperature (22°C) for 4 days followed by recovery temperature (28°C) for 28 days could obtain enhanced growth, that is overcompensation, with improved apparent digestibility coefficient, food conversion efficiency and energetic efficiency into growth. This technique would be more practically applicable in indoor culture for this species.     

Dietary myo‐inositol requirements of juvenile hybrid sturgeon (Acipenser baerii ♀ × A. schrenckii ♂)

This study was conducted to determine the optimal dietary myo‐inositol (MI) requirement of juvenile hybrid sturgeon (Acipenser baerii ♀ × A. schrenckii ♂). Fish with an initial average body weight of 28.28 ± 0.41 g were randomly divided into six groups with three repetitions in each group and fed the experimental diets with different graded MI concentrations (70.2, 130.0, 270.2, 443.0, 1,096.6 and 1997.3 mg/kg) three times per day for 12 weeks. The results showed that with the increase in dietary MI level from 70.2 mg/kg to 443.0 mg/kg, weight gain (WG) was increased significantly (p < .05); however, when the MI level was further increased, there was no significant difference in weight gain rate (WG) over time (p > .05). Specific growth rate (SGR) showed a similar trend. The feed conversion ratio (FCR), survival rate (SR), hepatosomatic index (HSI), viscerasomatic index (VSI) and condition factor (CF) were not affected by dietary MI supplementation (p > .05). Dietary MI did not affect whole‐body and muscle crude protein and ash content (p > .05), while dietary MI significantly affected the muscle and whole‐body crude lipid and moisture content (p < .05). Moreover, serum triglyceride (TG), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were decreased by increasing dietary MI levels. Total antioxidant capacity (T‐AOC), malonic dialdehyde (MDA) and superoxide dismutase (SOD) activities in the liver were also affected by the dietary MI (p < .05). In summary, this study indicated that the optimal dietary MI requirement for juvenile hybrid sturgeon (Acipenser baerii ♀ × A. schrenckii ♂) was 335.84 mg/kg and 590.65 mg/kg based on the maximum WG and liver MI accumulation indices respectively.     

Effects of a dietary administration of purple coneflower (Echinacea purpurea) on growth,antioxidant activities and 8 miRNAs expressions in crucian carp (Carassius auratus)

Echinacea purpurea (EP), a globally popular herbal medicine, has been used to treat various diseases in human and animals. However, little has been reported about its effects in fish. In this study, crucian carp (Carassius auratus) were selected to evaluate the effects of EP on growth performance and antioxidant response and the expressions of microRNAs. The results showed EP could stimulate the growth of crucian carp with the best effect was observed at dose of 4 g kg^?1. In serum, the content of hydroxyl radical (·OH) and malondialdehyde (MDA) decreased by EP supplementation, whereas the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione reductase (GR) increased. Similarly, the content of ·OH decreased, and the activities of CAT, GPX and GR increased in liver of crucian carp. Furthermore, in livers of crucian carp, EP supplements upregulated the expressions of the microRNAs (miR‐16, miR‐21, miR‐125b, miR‐146a, miR‐155, miR‐181a and miR‐223), which had been confirmed to participate in regulating antioxidant and immune function in mammals. Our results suggest EP supplements in diets stimulated growth performance and antioxidant response of crucian carp. In liver, the upregulation of specific miRNAs may participate in the antioxidant effects of EP diets.     

The effects of different fishmeal level diets with or without phytase supplementation on growth performance,body composition,digestibility, immunological and biochemical parameters of juvenile hybrid sturgeon (Acipenser baeri Brandt ♀ × A. schrenckii Brandt ♂)

A 12‐week growth trial was conducted to evaluate the effect of low fishmeal and phytase replacing inorganic phosphorus on juvenile hybrid sturgeon (Acipenser baeri Brandt ♀ × A. schrenckii Brandt ♂). Four experimental diets were designed as FM100p, FM100, FM250p and FM250, which represented 10% and 25% fishmeal with or without phytase, respectively. The results showed that although growth parameters had no significant difference in all treatments, low fishmeal obviously decreased the culture cost of hybrid sturgeon. Lipid content of body composition was obviously increased in low fishmeal treatments (p < .05). The interaction of low fishmeal and phytase significantly enhanced apparent digestibility coefficients of crude protein (p < .05). Two‐way ANOVA analysis showed that input and output of phosphorus were significantly affected by fishmeal level, phytase and interaction of both factors (p < .05). For the immunological and hepatic function parameters, fishmeal level and phytase had significant effects on the activities of lysozyme, myeloperoxidase, malondialdehyde, alanine aminotransferase, lactate dehydrogenase and alkaline phosphatase (p < .05). The present study potentially justifies that a diet containing 10% fishmeal can be used for hybrid sturgeon. Moreover, replacement of monocalcium phosphate by phytase not only has no adverse effect on the growth of hybrid sturgeon, but also reduces phosphorus emission and protects aquaculture environment.     

Influence of replacing fish meal with enzymatic hydrolysates of defatted silkworm pupa (Bombyx mori L.) on growth performance,body composition and non‐specific immunity of juvenile mirror carp (Cyprinus carpio var. specularis)

This study was conducted to investigate the effects of dietary supplementation of enzymatic hydrolysates of defatted silkworm pupa (EHDSP) on growth performance, body composition and non‐specific immunity of juvenile mirror carp (Cyprinus carpio var. specularis). The control diet (EHDSP0) was produced using fish meal (FM) as the main protein source and the other four diets were formulated by substitution of 25% (EHDSP25), 50% (EHDSP50), 75% (EHDSP75) and 100% (EHDSP100) FM with EHDSP. Five groups containing 270 juvenile mirror carp (14.51 ± 0.03 g) were fed to apparent satiation for 8 weeks. The results indicated that the special growth rate, weight gain, protein efficiency ratio and feed conversion rate of experimental fish in EHDSP25 and EHDSP50 groups were not significantly different from EHDSP0 group (p > .05). The spleen index of experimental fish in EHDSP25 group was significantly higher than that of EHDSP0 group (p < .05). The muscle protein content of experimental fish in EHDSP25 and EHDSP50 groups was significantly higher than that of EHDSP0 group (p < .05). Serum alanine aminotransferase and total cholesterol of experimental fish fed with the EHDSP were significantly lower than that of control (p < .05). The activity of serum superoxide dismutase of experimental fish in EHDSP25, EHDSP50 groups was significantly higher than that of EHDSP0 group (p < .05). Intestinal trypsin activity of EHDSP25 group was significantly higher than that of EHDSP0 (p < .05). In conclusion, EHDSP can be included into diet to replace 50% FM of juvenile mirror carp without negative effect on growth, furthermore, it can improve the non‐specific immunity and function of intestinal tract.