Review on Using of Macro Algae (seaweeds) in Fish Nutrition

Currently,the search is on for alternative sources of feed ingredients,the main reasons being the increasing cost and uncertainty about the continuous supply of common feed ingredients especially fishmeal and soybean meal.The importance of macro algae or seaweeds as a potential substitute protein source for fish nutrition cultured has been documented in recent years.Macro algae are receiving consideration for their essential amino acid content and high protein value,trace metals and vitamins in fish nutrition.In addition,macro algae or seaweeds could be a potential low cost source of protein for fishes.Furthermore,the economic comparison of feed cost revealed that the increase in the level of dried and fresh seaweeds in alternative feeding treatments,and commercial diets used for fish growth have decreased which led to a significant decrease in the cost of feed.From the results of previous studies,using of macro algae(seaweeds)in fish diets may improves growth performance,feed efficiency,physiological activity,carcass quality,disease resistance and reduced stress response.This review describes effects of using of macro algae(seaweeds)in diets on growth performance of fish.

Effect of Addition of Dried Beet-pulp on Silage Fermentation Quality of Fish Waste Inoculated with Lactic Acid Bacteria

[Objective] This study was to further enhance previous research in finding appropriate methods for preservation and utilization of fish waste.[Method]Fresh fish waste（head and viscera）from arabesque greenling（Pleurogrammus azonus）was mixed with dried beet-pulp and beet molasses at a ratio of 70：20：10 on fresh matter basis,respectively.These were inoculated with /without a commercial inoculant of Lactobacillus plantarum and ensiled at room temperature for 15,30,60 and 90 days.Fermentation quality and chemical composition of the silages were evaluated and a feeding trial conducted using hen layers with fish waste silage replacing 25% of a commercial formulated diet on dry matter basis.[Result] The concentration of lactic acid in the silages tended to increase with extension of the ensiling period and was significantly（P 〈 0.05）enhanced by the inoculant.The pH declined from 6.5 to around 4.4 during the first 15 days of the ensiling period and did not change much thereafter.The non-protein nitrogen（NPN）content increased two folds after 15 days in all silages relative to the material but the rate of volatile basic nitrogen（VBN）to total nitrogen（TN）was less than 10%.Feed intake and egg production was similar with replacement of 25% of the commercial formulated diet with fish waste silage.

Exploring the effects of dietary inulin in rainbow trout fed a high‑starch,100%plant‑based diet

Background High dietary carbohydrates can spare protein in rainbow trout(Oncorhynchus mykiss)but may affect growth and health.Inulin,a prebiotic,could have nutritional and metabolic effects,along with anti-inflammatory properties in teleosts,improving growth and welfare.We tested this hypothesis in rainbow trout by feeding them a 100%plant-based diet,which is a viable alternative to fishmeal and fish oil in aquaculture feeds.In a two-factor design,we examined the impact of inulin(2%)as well as the variation in the carbohydrates(CHO)/plant protein ratio on rainbow trout.We assessed the influence of these factors on zootechnical parameters,plasma metabolites,gut microbiota,production of short-chain fatty acids and lactic acid,as well as the expression of free-fatty acid receptor genes in the mid-intestine,intermediary liver metabolism,and immune markers in a 12-week feeding trial.Results The use of 2%inulin did not significantly change the fish intestinal microbiota,but interestingly,the high CHO/protein ratio group showed a change in intestinal microbiota and in particular the beta diversity,with 21 bacterial genera affected,including Ralstonia,Bacillus,and 11 lactic-acid producing bacteria.There were higher levels of butyric,and valeric acid in groups fed with high CHO/protein diet but not with inulin.The high CHO/protein group showed a decrease in the expression of pro-inflammatory cytokines(il1b,il8,and tnfa)in liver and a lower expression of the genes coding for tight-junction proteins in mid-intestine(tjp1a and tjp3).However,the 2%inulin did not modify the expression of plasma immune markers.Finally,inulin induced a negative effect on rainbow trout growth performance irrespective of the dietary carbohydrates.Conclusions With a 100%plant-based diet,inclusion of high levels of carbohydrates could be a promising way for fish nutrition in aquaculture through a protein sparing effect whereas the supplementation of 2%inulin does not appear to improve the use of CHO when combined with a 100%plant-based diet.

Advances in the Study on Nutrient Requirements of Grouper (Epinephelus sp.): a Review

The paper reviews the recent advances in studying grouper nutrition requirement for the development of cost-effective and environmentally friendly artificial diets. It consists of seven parts: protein and amino acid, lipid and essential fatty acid, carbohydrate, vitamin, mineral, alternative protein source, broodstock and larval nutrition. The review provides some basic information for further investigation of nutrient requirements of groupers.

Performance and Muscular Development of Nile Tilapia Larvae (Oreochromis niloticus) Fed Increasing Concentrations of Phenylalanine

Even though tilapia is of great economic interest, data on the nutritional requirements of amino acids during commercial breeding stages are scarce. So, the aim of this study was to analyse the performance and muscular growth of Nile tilapia larvae (Oreochromis niloticus) fed diets containing increasing concentrations of phenylalanine. The experiment took place at the Laboratory of Aquaculture of the Grupo de Estudos de Manejo na Aquicultura (GEMAq) of the Universidade Estadual do Oeste do Paraná (Unioeste), Toledo, PR, Brazil, for 30 days. A total of 450 larvae, with mean initial length of 1.5 ± 0.14 cm and mean initial weight of 0.04 ± 0.004 g, were randomly distributed into 6 treatment groups with 5 repetitions (30 tanks). Each experimental unit consisted of a 30 L tank containing 15 larvae. Six diets were formulated with increasing concentrations of phenylalanine (1.09, 1.24, 1.39, 1.54, 1.69 and 1.84%) and offered four times a day until apparent satiation. By the end of the experimental period, the following productivity indexes were analysed: length, weight, survival, weight gain, uniformity, feed conversion, specific growth rate and protein efficiency ratio. Three fish from each tank were collected for muscular growth analysis and the frequency of small ( 0.05) was observed in the productive performance parameters between the treatment groups. Thus, it can be concluded that the levels of phenylalanine contained in the experimental diets did not influence the performance of Nile tilapia larvae. However, there was more hyperplasia when we put 1.39% of phenylalanine in the diet.