Characteristics of perch fish diet in small lake of Lake Onega catchment area

Fish feeding process is studied as one of the links in the transformation of the energy of a water reservoir, as one of the factors that determine the ecology of fish and make an imprint on the morphology, physiology and behavior of fish, or as one of the criteria, which help the most rationally use natural resources of the water bodies. The results of work carried out by the Northern Water Problems Institute (NWPI KarRC RAS) and Petrozavodsk State University (PetrSU) within the framework of state assignments, forecast problems and economic contractual topics on assessing the nutrition of perch species (perch, ruff) in some lakes of the Konchezero group (South Karelia), in particular Lake Munozero, which is part of the lower reaches of the river Shuya belonging to the catchment area of Lake Onega. The work was carried out by the experts from the IWPS KarRC RAS and PetrSU in 2018-2020. Its main hydrological and ichthyological indicators have been studied. The reconnaissance fish productivity of Lake Munozero based on the development of the forage base at the present stage is estimated as 9 kg/ha. The feeding spectra of ruff and perch in the lake overlap only with respect to eggs, the ruff using eggs more actively. Predation is peculiar only to perch, while even fish whose size is less than 14 cm (the average size of the transition to predation for Karelia) hunt at a time when there is a lot of other food in the reservoir. As the perch passes to summer feeding, its diet becomes more diverse. Some benthic organisms are replaced by others, an air fraction appears, the perch's diet includes fish in summer and spring; nutrition becomes more active: the average stomach fullness index increases from 7.3 to 145.6‰.

Combined higher frequency fish consumption and healthy lifestyle may lower the triglyceride/HDL-C ratio in middle-aged Japanese males: Anti-atherosclerotic effect of fish consumption

Background: Fish consumption may be associated with a low risk of coronary artery disease. We aimed to investigate whether higher fish consumption results in improved lifestyle behaviors and thus lower triglyceride/high-density lipoprotein cholesterol (TG/HDL-C) ratio––a predictor of atherosclerotic cardiovascular disease (ASCVD). Methods and results: This cross-sectional study included 2947 middle-aged Japanese males with no history of ASCVD or lipid-modifying therapy, who presented at the Health Planning Center of Nihon university hospital between April 2018 and March 2019. We performed an analysis of variance using fish consumption as a categorical variable (0-2 days, 3-4 days, or 5-7 days per week). The serum TG/HDL-C ratio in the 5-7 days fish consumption group was significantly lower than those in the 0-2- and 3-4-days fish consumption groups (p < 0.0001 and p < 0.01, respectively). Multiple regression stepwise analysis revealed that weekly fish consumption negatively and independently determined the TG/HDL-C ratio (β = -0.061, p = 0.001). As fish consumption increased, the proportion of subjects with smoking habits decreased (p = 0.014), those engaging in aerobic exercises and aggressive daily physical activity increased (p < 0.0001 for both), and those with alcohol habit increased (p < 0.0001). In addition, we developed the risk stratification for ASCVD by combining the serum HDL-C level and the serum TG/HDL-C ratio with fish intake. Conclusion: Increased frequency of fish consumption and improved lifestyle behaviors due to daily fish intake may work additively to lower the serum TG/HDL-C ratio. These associations may explain why high fish consumption is associated with a lower risk of ASCVD. Our findings may help physicians and nutritionists in treating patients with heart diseases and metabolic conditions by recommending a high fish diet in middle-aged Japanese males.

Mealworm (Tenebrio molitor) potencial in fish nutrition: a review

The creation of aquatic organisms it is constantly growing and with this comes the need to meet this demand with the increased production of inputs such as feed for aquaculture. Fish nutrition is mainly characterized by the use of fish meal and oil for the manufacture of rations for their food. Soybean bran is the second most used ingredient as a source of protein in the production of feed for aquaculture. However, these ingredients compete with other feed segments, increasing cost or reducing market availability. Therefore, alternative sources of protein must be studied and developed to meet this demand. In this sense, insects present themselves as sources of high quality protein, in addition to fatty acids, vitamins and minerals. Although there is a problem with large-scale production to meet the demand of the feed market, the ease of breeding certain species of insects is capable of making this reality possible. Thus, insects can be a likely alternative protein source in fish feed, replacing conventional sources. This review aims to evaluate the inclusion of mealworm in the fish diet, in terms of performance and discuss the results obtained.

Utilization of fish waste as fish meal substitute in formulated fish diet on the growth performance of Nile tilapia fish fry (Oreochromis niloticus)

Fish meal is generally expended as the foremost protein supply in the fish diet. The rising cost of this component inflicted the aquaculture industry to seek a substitute in lessening the pellet cost. Thus, fish waste was tested in this study to investigate its viability. An experiment was performed to study the effects of fish waste and carcass on the growth performance of Nile tilapia fry. Solid fish waste of three different common species available in Mukah’s wet market was formulated into an artificial diet. The diet was formulated into three treatments consist of three protein levels (40%, 45% and 50%) with 4000 kcal/kg energy. A controlled group was fed with a commercial pellet consisting of 45% protein level. Fish were fed at 4% of body weight twice daily for 45 days. Fry reared in a controlled group was discovered highest weight gain, specific growth rate and length gain. There was no significant difference in all treatments for all parameters measured. The lowest weight gain and specific growth rate were recorded in fish fed 45% protein level (T2) group. Fish in T3 (50%) achieved the highest survival rate while T1 (40%) group recorded the lowest. The best and lowest Feed Conversion ratio (FCR) was recorded in the control group. In conclusion, the performance of formulated feed using fish waste is similar to commercial pellet as no significant difference can be observed in all parameters measured.

KOMPOSISI DAN LUAS RELUNG MAKANAN IKAN PALUNG (Hampala macrolepidota C.V.1823) DI WADUK PB. SOEDIRMAN BANJARNEGARA, JAWA TENGAH

This study aims to determine the composition and value of the natural feed niche of trough fish caught from the waters of the PB Reservoir. Sudirman. The research method used is a survey method with a sampling technique using purposive random sampling. The research location was divided into three stations, namely I (Karang Kemiri), II (Wanadadi), and III (Karang Jambe). Sampling was carried out three times (19 February, 07 March, and 2 August 2020). Data were analyzed descriptively comparatively. The results showed that the composition of the trough fish diet was dominated by Chlorophyta and plant debris. Based on the selectivity index and the most significant part of trough fish, including omnivorous fish. Large trough fish have a high food niche area. Small, medium and large trough fish have stiff competition for food in the waters

Sinomenine Hydrochloride Ameliorates Fish Foodborne Enteritis via α7nAchR-Mediated Anti-Inflammatory Effect Whilst Altering Microbiota Composition

Foodborne intestinal inflammation is a major health and welfare issue in aquaculture. To prevent enteritis, various additives have been incorporated into the fish diet. Considering anti-inflammatory immune regulation, an effective natural compound could potentially treat or prevent intestinal inflammation. Our previous study has revealed galantamine’s effect on soybean induced enteritis (SBMIE) and has highlighted the possible role of the cholinergic anti-inflammatory pathway in the fish gut. To further activate the intestinal cholinergic related anti-inflammatory function, α7nAchR signaling was considered. In this study, sinomenine, a typical agonist of α7nAChR in mammals, was tested to treat fish foodborne enteritis via its potential anti-inflammation effect using the zebrafish foodborne enteritis model. After sinomenine’s dietary inclusion, results suggested that there was an alleviation of intestinal inflammation at a pathological level. This outcome was demonstrated through the improved morphology of intestinal villi. At a molecular level, SN suppressed inflammatory cytokines’ expression (especially for tnf-α) and upregulated anti-inflammation-related functions (indicated by expression of il-10, il-22, and foxp3a). To systematically understand sinomenine’s intestinal effect on SBMIE, transcriptomic analysis was done on the SBMIE adult fish model. DEGs (sinomenine vs soybean meal groups) were enriched in GO terms related to the negative regulation of lymphocyte/leukocyte activation and alpha-beta T cell proliferation, as well as the regulation of lymphocyte migration. The KEGG pathways for glycolysis and insulin signaling indicated metabolic adjustments of α7nAchR mediated anti-inflammatory effect. To demonstrate the immune cells’ response, in the SBMIE larva model, inflammatory gatherings of neutrophils, macrophages, and lymphocytes caused by soybean meal could be relieved significantly with the inclusion of sinomenine. This was consistent within the sinomenine group as CD4+ or Foxp3+ lymphocytes were found with a higher proportion at the base of mucosal folds, which may suggest the Treg population. Echoing, the sinomenine group’s 16s sequencing result, there were fewer enteritis-related TM7, Sphingomonas and Shigella, but more Cetobacterium, which were related to glucose metabolism. Our findings indicate that sinomenine hydrochloride could be important in the prevention of fish foodborne enteritis at both immune and microbiota levels.

Using tuna fish bone waste as mineral sources in feed formulation of tilapia (Oreochromis niloticus)

Fish bone is a solid waste that usually found in traditional fish markets of Ternate. The bone fraction contains high minerals such as calcium, phosphorus, and collagen proteins which are important for fish growth. Tuna fish bone waste was processed into dry fish feed and mixed into feed formulation of Tilapia. Four different dose of tuna fish bone powder were applied namely 0%, 1%, 3%, and 5% as mentioned treatment A, B, C, and D. Fish diet were given to Tilapia juvenile for 42 days. Results show that the body weight and specific growth rate are highest in fish which given 3% dose of tuna fish bone than other treatments. It reaches 38.66 g and 9.617% BW/day. The lowest FCR is 1.34 in treatment C and the survival rate is not significantly different among treatments (p>0.05).

Increasing growth and survival rate of tilapia larvae (Oreochromis niloticus) by adding polychaeta Nereis sp dry meal into feed formulation

Aquaculture has been known as one of solutions in dealing with food security problem through applying best practices of aquaculture and increasing fish production. In many countries, fish production is considered an essential activity contributing to household income and trade. However, fish feed has an expensive price, and it constitutes 60-70% total cost of production. The objective of this study is to reveal an alternative cheap source for additional ingredients to fish diet formulation of Tilapia larvae (Oreochromis niloticus). 240 fish larvae from local hatchery were used and cultured in 4 aquariums with different dose of protein diet (30%, 35%, 40%, and control). The source of protein diet is Polychaeta Nereis sp which was collected from surrounding Kastela Sea. Nereis sp was processed into dry meal and was added into the feed formulation. The result shows that the useful of 40% protein of Nereis sp gives the highest growth and survival rate of tilapia larvae, which is 44,99 g and 100%. It is followed by 35% and 30% Nereis protein, respectively. It is interesting that protein control which is feed commercial has almost similar growth level as the highest one. Specific growth rate (SGR) is 3,74%-3,79% per day for different protein dose of Polychaeta. Survival rate is 100% for all treatments which means all fish can survive and growth continuously from beginning to the end of the study.

Microbiota composition and intestinal integrity remain unaltered after the inclusion of hydrolysed Nannochloropsis gaditana in Sparus aurata diet

The use of lysed microalgae in the diet of carnivorous fish can increase the bioavailability of proteins and bioactive compounds, such as unsaturated fatty acids or vitamins in the digestive tract. These are essential molecules for the proper physiological development of fish in aquaculture. However, some antinutritional components and other undesirable molecules can be released from an excess of microalgae supplied, compromising the integrity of the intestine. The inclusion of small amounts of hydrolized microalgae in the fish diet can be a good strategy to avoid negative effects, improving the availability of beneficial compounds. Nannochloropsis gaditana is an interesting microalgae as it contains nutraceuticals. Previous studies reported beneficial effects after its inclusion in the diet of Sparus aurata, a widely cultured species in Europe and in all Mediterranean countries. However, administration of raw microalgae can produce intestinal inflammation, increased intestinal permeability, bacterial translocation and disturbance of digestion and absorption processes. The aim of this study was to evaluate changes in the intestinal microbiota and barrier stability of S. aurata fed with low inclusion (5%) hydrolysed N. gaditana. Intestinal microbiota was analyzed using Illumina MiSeq technology and libraries were constructed using variable regions V3–V4 of 16S rDNA molecules. Analysis were based in the identification, quantification and comparison of sequences. The predictive intestinal microbial functionality was analyzed with PICRUSt software. The results determined that the intestinal microbiota bacterial composition and the predictive intestinal microbiota functionality did not change statistically after the inclusion of N. gaditana on the diet. The study of gene expression showed that genes involved in intestinal permeability and integrity were not altered in fish treated with the experimental diet. The potential functionality and bacterial taxonomic composition of the intestinal microbiota, and the expression of integrity and permeability genes in the intestine of the carnivorous fish S. aurata were not affected by the inclusion of hydrolysed 5% N. gaditana microalgae.