INTERACTION BETWEEN DIETARY MINERAL AND PHYTASE ON BIOLOGICAL PERFORMANCES OF JAPANESE FLOUNDER, Paralichthys olivaceus. PART II. MINERAL DIGESTIBILITY AND VERTEBRAL MINERAL CONTENT

Interactive effects between dietary inorganic phosphorus (IP) and phytase (P) on mineral digestibility and vertebral mineral content were investigated in a 30 days feeding trial followed by three weeks digestibility trial with Japanese flounder, Paralichthys olivaceus. Eight experimental diets were formulated based on two levels of dietary Ca at 0% and 0.2% combined with either 0% or 0.25% of dietary IP and either with 0 and 2,000 fytase unit (FTU)/kg of phytase in diet, respectively. Result indicated that digestibility of total phosphorus significantly increased by three dietary compounds where the highest was observed in fish fed diet contained 0.25% IP and 2,000 FTU phytase/kg and dietary Ca also included in diet. Significant interaction was only detected between dietary IP and P on this parameter. Supplementation of IP and Ca not phytase significantly improved Ca digestibility. Ca digestibility was very poor when dietary IP and Ca were not supplemented in diet even with when phytase supplemented in diet. There was significant interaction between dietary IP and Ca on Ca digestibility. Vertebral total phosphorus, Ca, and Mg content as well as Ca:P ratio were significantly enhanced by dietary IP and phytase. Dietary Ca has significant effect only on vertebral total phosphorus. Interaction between dietary IP and Ca was significantly found on vertebral Ca content and Ca:P ratio. No significant second-order interaction was observed among the three dietary mineral on overall parameters. Based on total phosphorus and Ca digestibility as well vertebral phosphorus content found in this study, dietary IP, Ca, and phytase at rate of 0.25%, 0.2%, and 2,000 FTU phytase/kg diet, respectively are needed to supplement in diet for a better mineral absorption and bone mineralization

FLUCTUATION OF POST-PRANDIAL PLASMA MINERAL LEVEL OF JUVENILE JAPANESE FLOUNDER, Paralichthys olivaceus FED DIETARY PHOSPHORUS AND PHYTASE SUPPLEMENTATION

In order to investigate the phytic acid degradation in the gut of post juvenile Japanese flounder, indirect method was carried out by measuring the pre-prandial and postprandial plasma mineral and alkaline phosphatase (ALP) level as well as liver phosphorus content. The experiment was designed into a Randomized Block in which experiment units were grouped according to sampling days at 10, 20 and 30 days of feeding time. Experimental diets contained three levels of dietary inorganic phosphorus at 0.0; 0.25 and 0.5% combined with two levels of dietary phytase at 0 and 2,000 FTU/kg diet. Juvenile Japanese flounder (IBW = 36.2 g) were randomly distributed into 6 tanks of a 200 L capacity with density of 15 fish/tank. Blood sampling was carried out at 0 hour (before feeding or pre-prandial) and at 1, 3, 6 and 12 hour post feeding (post-prandial) time in three sampling days, respectively. Plasma was measured for mineral and ALP levels, while liver was analyzed for P content. The observation showed that fish fed without both dietary IP and phytase supplements had the lowest postprandial plasma IP, Mg and ALP levels during 12-h postprandial period. Plasma IP level at 6-h post-feeding in groups fed dietary 0.25 and 0.5% IP were significant higher when diet supplemented with phytase than those without phytase supplement. Peak level of plasma IP in fish fed 0.25% IP was similar to fish fed 0.5% with the presence of dietary phytase. At 1 and 3-h post-feeding, plasma Ca level increased in all groups, but significant difference was only observed between group fed diet without both dietary IP and phytase and other groups. Similar to plasma IP level, peak of plasma Mg and ALP concentration occurred in fish fed 0.25% IP together with phytase, and did not significantly differ from fish fed with 0.5% IP even when phytase was included in diet

Hydrolyzed Tuna Meat By-Product Supplement for Juvenile Red Sea Bream, Pagrus major, and its Effect on Growth, Enzyme Activity, Plasma Parameters, and Apparent Nutrient Digestibility

A growth experiment was conducted on juvenile red sea bream, Pagrus major to investigate the effect of the inclusion in fish diets, of tuna meat by-product hydrolysate which was processed through enzymatic hydrolysis using a commercially available enzyme, derived from Bacillus subtilis. Six experimental diets were formulated in the experiment. Three diets contained 50, 150 and 250 g/kg of TPM-H (tuna meat by-product hydrolysate), and two diets with the unprocessed TPM (tuna meat by-product) at an inclusion level of 50 and 250 g/kg. A control diet was formulated without any addition of the test ingredients. Treatment diets were fed ad libitum to juvenile fish with an initial average body weight of 0.81 ±0.13 g for 56 days. Results of the feeding trial suggest that the inclusion of TPM-H at 250 g/kg in fish diets improved body weight gain rate (3271.58%), feed intake (24.55 g/fish/56 days) and feed conversion efficiency (1.12) of the fish. Apparent nutrient digestibility of hydrolyzed tuna meat by-product improved compared to the unhydrolyzed ingredient. These results suggest that TPM processed as hydrolysates can be efficiently utilized by fish

Vitamin A effects and requirements on the juvenile Kuruma Prawn Marsupenaeus japonicus

A 40-day feeding experiment was conducted to assess the effect and requirements of dietary vitamin A (vitA) of juvenile Kuruma Prawn Marsupenaenus japonicus. Nine semi-purified diets were prepared with supplementations of 0, 3,000, 6,000, 9,000, 12,000, 15,000, 18,000, 21,000 and 24,000 international units of vitA per kg (IU vitA/kg) and fed once a day to triplicate groups of 15 juveniles per tank (initial weight of 0.14 ± 0.001 g, mean ± standard error). Weight gain (WG), specific growth rate (SGR) and feeding efficiency ratio (FER) were significantly lower in the juveniles fed with the diets contained 0 and 3,000 IU vitA/kg than in the other groups. Similar values of total retinol (ROL) in whole body were detected only in the juveniles fed on the diets supplemented with 21,000 and 24,000 IU vitA/kg: 10.22 ± 2.74 and 10.70 ± 0.14 ?g ROL /g of wet weight, respectively (mean ± standard error). It was not possible to detect retinal in the whole body samples in any of the experimental groups. According to the WG analyzed by the broken line regression, the dietary requirements of vitA should be of 7,500 IU vitA/kg

Effect of Substituting Fish Oil with Camelina Oil on Growth Performance, Fatty Acid Profile, Digestibility, Liver Histology, and Antioxidative Status of Red Seabream (Pagrus major)

A 56-day feeding trial to evaluate the responses of red seabream (initial weight: 1.8 ± 0.02 g) to the substitution of fish oil (FO) with camelina oil (CO) at different ratios was conducted. The control diet formulated at 46% CP (6F0C) contained only FO without CO; from the second to the fifth diet, the FO was substituted with CO at rates of 5:1 (5F1C), 4:2 (4F2C), 3:3 (3F3C), 2:4 (2F4C), and 0:6 (0F6C). The results of the present study showed that up to full substitution of FO with CO showed no significant effect on growth variables BW = 26.2 g–28.3 g), body weight gain (BWG = 1275.5–1365.3%), specific growth rate (SGR = 4.6–4.7), feed intake (FI = 25.6–27.8), feed conversion ratio (FCR = 1.0–1.1), biometric indices condition factor (CF = 2.2–2.4), hepatosomatic index (HSI = 0.9–1.1), viscerasomatic index (VSI = 7.5–9.5), and survival rates (SR = 82.2–100) with different FO substitution levels with CO. Similarly, there were no significant differences (p < 0.05) found in the whole-body composition except for the crude lipid content, and the highest value was observed in the control group (291 g/kg) compared to the other groups FO5CO1 (232 k/kg), FO4CO2 (212 g/kg), FO2CO4 (232 g/kg) and FO0CO6 (244 g/kg). Blood chemistry levels were not influenced in response to test diets: hematocrit (36–33%), glucose (Glu = 78.3–71.3 mg/dL), total protein (T-pro = 3.1–3.8 g/dL), total cholesterol (T-Chol = 196.0–241 mg/dL), blood urea nitrogen (BUN = 9.0–14.6 mg/dL), total bilirubin (T-Bil = 0.4–0.5 mg/dL), triglyceride (TG = 393.3–497.6 mg/dL), alanine aminotransferase test (ALT = 50–65.5 UL/L), aspartate aminotransferase test (AST = 38–69.3 UL/L). A remarkable modulation was observed in catalase (CAT) and superoxide dismutase (SOD) activities in the liver, as CAT and SOD values were lower with the complete FO substitution with CO (0F6C), and the highest values were observed in the control and (4F2C). This study indicates that red seabream may have the ability to maintain LC-PUFAs between tissues and diets, and CO substitution of FO could improve both lipid metabolism and oxidation resistance as well as maintain digestibility. In conclusion, dietary FO can be replaced up to 100% or 95% by CO in the diets of red seabream as long as n-3 HUFA, EPA, and DHA are incorporated at the recommended level

Immunotherapies Targeting Fish Mucosal Immunity – Current Knowledge and Future Perspectives

In recent years studies on the mucosal immunity in fish species have shown much progress. Although there are some organs such as skin, gills, and gut which are directly associated with the mucosal immunity of fish species, this mini review emphasizes the general knowledge on the role and production figures of skin mucus and factors affecting the secretion of skin mucus of fish species. As the skin mucus of fish species is the first defense line for protection against invading microorganisms such as pathogens (bacteria, virus), parasites, etc., the information for understanding the roles of the skin mucus is very important. Furthermore, the information in the review will shed light on the development of high quality aquafeeds for the sustainable aquaculture field as well

The Protein Sparing Effects Of High Lipid Levels In Diets For Rainbow Trout (Oncorhynchus Mykiss, W. 1792) With Special Reference To Reduction Of Total Nitrogen Excretion

This research sought to develop low-protein, high-energy (less-polluting) diets for rainbow trout to properly utilize protein and reduce total nitrogen excretion. Duplicate groups of rainbow trout were fed one of four experimental diets with a protein to energy (P:E) ratio of 25, 24, 22 or 19 mg/kJ and a lipid content of 12, 13, 17 or 26%, respectively. The diets were given to fish with a mean initial weight of 181 g for 70 days. At the conclusion of the trial, mean weights ranged from 353.17 g (94% weight gain) to 394.75 g (118% weight gain) with 100% survival in all treat- ments. Weight gain, feed efficiency and protein retention increased as the dietary lipid content increased and as the P:E ratio decreased. Fish fed the 22 mg protein/kJ energy diet (17% lipid, 44% protein, 20.34 kJ/g gross energy) performed best. This indicates that the protein content in practical trout feeds can be reduced from the currently used 47% to around 44% without reduc- ing the growth rate and feed efficiency, if high quality protein is used and the gross energy is increased by lipid to about 20.34 kJ/g diet. The low-protein, high-energy diets reduced the total nitrogen excretion from the rainbow trout by 27%

Status of development and use of alternative dietary ingredients in aquaculture feed formulations in Japan: Recent progress of fish meal replacement study of marine fish

Fish meal (FM) reduction in aquafeeds is one of the most important issues in aquaculture in Japan. The progress in research studies on reducing the amount of FM in aquafeeds has been demonstrated in several marine species in recent years. This report summarizes those on three species which are high-valued and intensively cultured in Japan; namely, the red sea bream, the amber jack and the Kuruma shrimp