Affect Fish Growth Research Articles

Effects of short‐term temperature changes on the physiology, biochemistry and feeding behaviour of the juvenile yellow seahorse— Hippopotamus kuda Bleeker

In order to study the impact of acute temperature challenge on juvenile hippocampus's growth, the variations of external behavioural indexes and internal physiological, biochemical and genetic indexes were analysed at the same time under acute temperature change. In this paper, the external indexes we selected were the response parameters of feeding behaviour (including feeding reaction time, feeding rate and food intake, etc.). The internal indicators include biochemical indicators (SOD, CAT, AKP, ACP, Trypsin, LPS and AMS enzyme activity and MDA content) and fold change (differentially expression multiples) of differentially expressed gene (Hsp70, Hsp90, Gst, Pyy, mTOR, Bcl-2, Casp9, Casp3, Gadd45α, Fadsd6, Cpt1, Fas, Cyp51, Pdha1, Mdh1, Idh3b and G6pd). The results showed that the juvenile's external indexes had changed significantly at 12 h after short-term temperature challenge exposed. At the same time, the feeding reaction time (s) was extend, and the feeding rate (individuals/min) and food intake (individual) were reduced, suggesting that the growth of juvenile might be suppressed by temperature challenge. At the same time, MDA and AMS showed a significant correlation with the feeding behaviour parameters, and several function genes Gadd45α, Casp3, Idh3b and G6pd also showed a correlation with the behavioural parameters. Our study provide a valuable information for understanding the mechanism of internal and external reaction in juvenile seahorse, which exposed to short-term temperature challenge. It is useful to explore the mechanism of how temperature affects fish growth. And the external behavioural indexes can correctly reflect the excessive fluctuation of environmental temperature that is harmful to the juvenile.

Otolith Microstructure Analysis Elucidates Spawning and Early Life Histories of Federally Endangered Fishes in the San Juan River

The short larval ontogenetic phase has a large impact on success or failure of fish populations due to naturally high mortality rates. Yet, for the federally endangered fishes Colorado Pikeminnow Ptychocheilus lucius and Razorback Sucker Xyrauchen texanus, information about this sensitive life stage is limited. We determined species-specific age–length functions, spawning periodicity, and environmental factors related to growth and the onset of spawning by these species in the San Juan River of the Colorado River basin. Daily ages were determined from lapillar otoliths, and growth rates were calculated for subsamples of San Juan River larval Colorado Pikeminnows and Razorback Suckers collected from 2009 through 2017 and six candidate age–length functions were fit to evaluate the relationship between age and growth. Spawning periodicity estimates from the best-fit-model and published function were compared to those from observed otolith ages and differences were analyzed. The responses of spawning periodicity and growth to abiotic and temporal conditions were evaluated. For both species, spawning dates produced by otolith ages and best-fit functions were significantly different from those produced by the published functions, but not from each other. Age–length functions determined in this study enable more accurate back-calculation of ages and prediction of spawning periodicity than published functions. The spawning periodicity estimate of San Juan River Colorado Pikeminnow and Razorback Sucker were both impacted by multiple parameterizations of temperature and discharge. For both species, fish age had the biggest influence on growth. Accurate knowledge of spawning periodicity and factors affecting fish growth can improve timing of management activities to maximize benefit to Colorado Pikeminnows and Razorback Suckers in the San Juan River.

Deciphering dissolved organic matter from freshwater aquaculture ponds in Eastern China based on optical and molecular signatures

Aquaculture makes great contribution to global food production. The aquaculture capture scale of China was far ahead of other countries in the world. Despite the potential role of dissolved organic matter (DOM) to affect fish growth and ecological cycle, the characterization of DOM in aquaculture industry was poorly understood. In this study, fluorescence excitation-emission matrix (EEM) spectroscopy and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) were conducted to decipher the optical and molecular signatures of DOM in freshwater aquaculture ponds in Eastern China. The EEM dataset was decomposed by parallel factor analysis (PARAFAC). Three main components including humic/fulvic acid-like (C1 and C3), tryptophan-like (C2) and tyrosine-like substances (C3) were obtained. FT-ICR-MS identified DOM composition at molecular level. In terms of formula classes, the dominant CHO species were followed by CHON and CHOS groups. According to compound classification criteria, the key components of lignins, tannins, proteins and lipids illustrated the primary source from terrestrial sediment, feeding doses and stocked creatures, implying the great influence by the land-based aquaculture ponds. Typical spectral indexes such as humification index (HIX), biological index (BIX) and fluorescence index (FI) consistently reflected the lower humification degree of DOM and greater contribution from protein-like sources. Furthermore, to utilize readily available spectral indexes to predict the time-consuming molecular properties, redundancy analysis and the pairwise correlation analysis was carried out to prove that two spectral indexes (E2:E3 and BIX) were negatively associated with four molecular formula derived parameters (O/Cwa, AImodwa, DBEwa and NOSCwa). The findings expanded our understanding of aquaculture DOM evolved in environmental chemistry.

Dietary sodium butyrate supplementation attenuates intestinal inflammatory response and improves gut microbiota composition in largemouth bass (Micropterus salmoides) fed with a high soybean meal diet.

The study aimed to investigate the effects of dietary sodium butyrate (NaBT) supplementation on the gut health of largemouth bass (Micropterus salmoides) fed with a high soybean meal diet. Three isonitrogenous and isolipidic diets were formulated: a high fishmeal group (Control); a high soybean meal group (SBM), in which the 30% fishmeal protein in the Control diet was replaced by soy protein; and an NaBT group, in which 0.2% NaBT was added to the SBM diet. Each diet was fed to triplicate tanks (20 fish in each tank). After 8weeks of feeding trial, the distal intestine and intestinal digesta of the fish in each treatment were sampled. The results showed that fishmeal replacement and NaBT supplementation did not affect fish growth performance. Dietary 0.2% NaBT supplementation improved intestinal morphology, increasing the villus width and villus height and reducing the width of lamina propria. The distal intestine of fish in the control and NaBT groups demonstrated lower activities of total superoxide dismutase (T-SOD) and glutathione peroxidase (GPx) and a lower malondialdehyde (MDA) content, compared with the fish in the SBM group. Moreover, the addition of 0.2% NaBT in the feed significantly decreased the expression of tumor necrosis factor α (TNF-α) and interleukin 1β (IL-1β) compared to the SBM diet. PCoA and UPGMA analyses based on weighted UniFrac distances demonstrated that intestinal microbial communities in the NaBT group were closer to those in the control group than to those in the SBM group. In addition, dietary 0.2% NaBT supplementation significantly increased the abundance of Firmicutes and Bacteroidetes and decreased the abundance of Tenericutes at the phylum level. Furthermore, the abundance of Bacteroides, Lachnospiraceae_unclassified, and Lachnospiraceae_uncultured was significantly increased, while that of Mycoplasma was significantly decreased in fish intestine at NaBT group at the genus level. In conclusion, dietary NaBT supplementation had beneficial roles in protecting the gut health of largemouth bass from the impairments caused by soybean meal.

Effects of dietary linolenic acid to linoleic acid ratio on growth performance, proximate composition and fatty acid contents of pacu ( Piaractus mesopotamicus )

Freshwater fish have the ability to convert linolenic acid (LNA) into EPA and DHA and linoleic acid (LA) into ARA from elongation and desaturation process. The optimal LNA/LA in aquafeeds formulated with vegetable oils can improve the n-3/n-6 ratio in fish flesh. This study aimed at determining the effects of varying dietary LNA/LA ratios on the growth and proximate composition and fatty acids content in the flesh of pacu, Piaractus mesopotamicus. Juvenile pacu (110 ± 1.6 g) were fed for 60 days with diets containing varying levels of sunflower (SO) and linseed (LO) oils (100SO; 75SO:25LO; 50SO:50LO; 25SO:75LO; 100LO), and performance and proximate composition and fatty acids contents of fish flesh were analysed. Experimental diets did not affect fish growth performance. Although the EPA and DHA content were lower in the fish fed the experimental diets than control diet (fish oil), the complete replacement of fish oil by an approximate proportion of 12SO:88LO, in an optimal LNA/LA ratio (2.2–2.4), represents an improvement in nutraceutical quality of the flesh for human consumption. Fish-fed ideal LNA/LA ratio diets have higher total n-3 fatty acids contents, and higher n-3/n-6 and EPA/ARA ratios, without hampering fish performance and flesh proximate composition.

Effects of dietary supplementation with filamentous microalgae (Oedocladium sp. or Tribonema ultriculosum) on growth performance, fillet fatty acid composition, skin pigmentation, and immune response of yellow catfish Pelteobagrus fulvidraco

AbstractA 40‐day feeding trial was conducted to investigate the effect of dietary microalgae Oedocladium sp. or Tribonema ultriculosum supplementation on growth performance, fillet fatty acid composition, skin pigmentation, and immune response of yellow catfish Pelteobagrus fulvidraco. Two hundred and seventy experimental fish (51.19 ± 1.17 g) were distributed among nine net cages (2 × 2 × 2 m3) in a randomized design and were fed diets containing 0% (control), 4% Oedocladium meal (Oedocladium), and 5% T. utriculosum meal (Tribonema) to apparent satiation twice a day. After the feeding trial, a hypoxic stress test was conducted to evaluate the effect of dietary microalgal supplementation on fish immune response. Compared to the control, microalgal supplementation did not affect fish growth performance. Dietary supplementation of T. utriculosum significantly increased fillet contents of palmitoleic acid by 100.44% and eicosapentaenoic acid by 12.51%, while the supplementation of Oedocladium meal in diet significantly increased the fish skin ventral lutein content by 61.6%. In addition, dietary Oedocladium or T. utriculosum supplementation significantly increased the plasma total superoxide dismutase activity (before hypoxic stress) and complement component 3 contents (after hypoxic stress). The addition of T. utriculosum meal also significantly increased the plasma immunoglobulin M content regardless of hypoxic stress. These results demonstrated Oedocladium sp. and T. utriculosum can be used to enhance fillet nutritional quality, skin pigmentation, and fish immune response.

Transcriptomic analysis to elucidate the effects of high stocking density on grass carp (Ctenopharyngodon idella)

BackgroundGrass carp (Ctenopharyngodon idella) is one of the most widely cultivated fishes in China. High stocking density can reportedly affect fish growth and immunity. Herein we performed PacBio long-read single-molecule real-time (SMRT) sequencing and Illumina RNA sequencing to evaluate the effects of high stocking density on grass carp transcriptome.ResultsSMRT sequencing led to the identification of 33,773 genes (14,946 known and 18,827 new genes). From the structure analysis, 8,009 genes were detected with alternative splicing events, 10,219 genes showed alternative polyadenylation sites and 15,521 long noncoding RNAs. Further, 1,235, 962, and 213 differentially expressed genes (DEGs) were identified in the intestine, muscle, and brain tissues, respectively. We performed functional enrichment analyses of DEGs, and they were identified to be significantly enriched in nutrient metabolism and immune function. The expression levels of several genes encoding apolipoproteins and activities of enzymes involved in carbohydrate enzymolysis were found to be upregulated in the high stocking density group, indicating that lipid metabolism and carbohydrate decomposition were accelerated. Besides, four isoforms of grass carp major histocompatibility complex class II antigen alpha and beta chains in the aforementioned three tissue was showed at least a 4-fold decrease.ConclusionsThe results suggesting that fish farmed at high stocking densities face issues associated with the metabolism and immune system. To conclude, our results emphasize the importance of maintaining reasonable density in grass carp aquaculture.

Higher growth variability and stronger responses to temperature changes in wild than hatchery-reared sea trout (Salmo trutta L.).

Each year, millions of hatchery‐reared sea‐run brown trout Salmo trutta L. (the sea trout) juveniles are released into the natural environment in the Atlantic region. The aim of this work was to investigate the growth responses of sea trout to changing temperature conditions and to compare the growth plasticity between wild and hatchery‐reared fish. Scales were collected from sea trout in a selected river flowing into the southern Baltic Sea. We analyzed the scale increment widths as a proxy of somatic growth and investigated the interannual variabilities and differences in growth between fish groups (wild and hatchery‐reared). We used mixed‐effects Bayesian modeling and ascribed the variances in growth to different sources. Furthermore, we developed indices of interannual (2003–2015) growth variation in the marine and freshwater phases of the life cycle of the fish and analyzed the relationships between trout growth and temperature. Temperature positively affects fish growth, regardless of the origin of the fish. We observed stronger relationships between fish growth and temperature conditions in the marine phase than in the freshwater phase. Additionally, wild sea trout are characterized by stronger responses to temperature variability and higher phenotypic plasticity of growth than those of the hatchery‐reared individuals. Therefore, wild sea trout might be better suited to changing environmental conditions than hatchery‐reared sea trout. This knowledge identifies possible threats in management actions for sea trout with an emphasis on ongoing climate change.

Effect of different stocking densities on fish growth performance: A meta-analysis

Density is an important aquaculture parameter which has a remarkably impact on variable fish growth performance. However, many scattered studies of density on individual fish have hindered understanding of its roles in growth of fish from different families. The present study attempted to explore the effects of density on fish growth. We found two levels of the optimal density and corresponding weight via density-weight fitted curve: 0-28 g body masses with the optimal densities from 1.76 to 14.55 kg·m−3; 7.17–98.33 g body masses with the optimal densities from 14.55 to 38.38 kg·m−3. The forest plots indicate that the most fish SGR values were significantly improved in low density. However, high heterogeneities were found in above four parameters. But no obvious publication bias was found in survival, CF, SGR and FCR, suggesting that the high heterogeneities is originated from animals, diet and experimental design. The Principle Component Analysis (PCA) further validated that the optimal density is one of the most key factors and it has obvious negative correlation with several Temperature/Dissolved oxygen, suggesting relevance among density, growth, and water quality/feeding regime. We speculated that the density could strongly influence fish growth through altering hematological and plasmatic phenotypes. We further focused on two of three pivotal enzymes, the CS, IDH, are highly possible in response to overcrowding stress in Kreb's cycle and they could further affect fish growth. This study explored the correlation between optimal density and fish body masses for the first time. Current results will provide theoretical guidance for fish growth and healthy aquaculture.

Fitting growth models to otolith increments to reveal time-varying growth

Identifying changes in fish growth is important for accurate scientific advice used for fisheries management, because environmental change is affecting fish growth and size-at-age is a critical component of contemporary stock assessment methods. Growth-increment biochronologies are time series of growth-increments derived from hard parts of marine organisms that may reveal dynamics of somatic fish growth. Here we use time series of otolith increments of two fish stocks to fit and compare a biologically derived growth model and a generalized statistical model. Both models produced similar trajectories of annual growth trends, but the biologically based one was more precise and predicted smaller interannual fluctuations than the statistical model. The biologically based model strongly indicated covariance between anabolic and catabolic rates among individuals. Otolith size-at-age did not closely match fish length-at-age, and consequently the growth model could not accurately hindcast observed fish length-at-age. For these reasons, fitted growth dynamics from otolith biochronologies may best suited to identify growth rate fluctuations, understand past drivers of growth dynamics, and improve ecological forecast in the face of rapid environmental change.

Can improved nutrition for Atlantic salmon in freshwater increase fish robustness, survival and growth after seawater transfer?

The loss of fish in the seawater (SW) phase of Atlantic salmon farming is high, and a major proportion of this loss occurs in the period just after SW transfer. In the current study, we hypothesize that improvements made to the diet during the freshwater (FW) stage affect fish growth, survival and robustness later in the SW stage. To test this, salmon parr were fed five experimental diets in FW at 12 °C. In addition to a commercial-like control diet, fish were fed a diet with changed FA composition aimed to be more like the natural feed of salmon in FW, a diet with increased concentrations of selected AA/N-compounds (methionine, lysine, threonine and taurine), a diet with increased concentrations of methionine and certain B-vitamins (folate, B12 and B6) and a final diet combining all of these potential improvements. At the time of SW transfer, the robustness of fish fed the different diets was tested by direct transfer to SW at three different temperatures (8, 12 and 16 °C, without prior acclimation), as well as transfer into open net pens, while fed on a common commercial diet. Growth and proximate composition of the fish did not differ between the diet groups. All diet groups seemed to handle transfer to SW well, and while SW transfer elicited a stress response in the fish, this was not significantly different between diet groups. Fish transferred to SW at 8 °C had higher mortality, reduced mucus layer and increased prevalence of scale loss and wounds, but this applied to all diet groups. Hence, direct transfer to SW at a lower temperature than the fish has been acclimated to cannot be recommended. At the two highest temperatures, there were some differences between the groups in the severity of cataracts. Apart from this, none of the health- or welfare related parameters measured showed any difference between the diet groups, indicating that the control diet was already sufficient.

Mechanisms by Which Fermented Soybean Meal and Soybean Meal Induced Enteritis in Marine Fish Juvenile Pearl Gentian Grouper.

Soy meals can cause intestinal inflammation and even injury in animals, especially infants and juvenile individuals. This study investigated the effects of fermented soybean meal (FSBM) on the growth and intestinal homeostasis of juvenile pearl gentian grouper and examined the mechanisms by which FSBM and soybean meal (SBM) induced enteritis in fish, using “3+2” full-length transcriptome sequencing. We randomly assigned 720 female juvenile groupers into three treatment groups: FM control group, 20% FSBM group (FSBM20), and FSBM40 group (n = 4). Three iso-nitrogenous (50% protein) and iso-lipidic (10% lipid) diets were prepared and fed to fish for 10 weeks. The water volume in each barrel was about 1 m3, using natural light and temperature. Results showed that dietary FSBM, at experimental level, significantly affected fish growth and intestinal structure negatively and significantly increased enteritis indices. The degree of intestinal injury and inflammation was determined by the enzyme activities of trypsin and lysozyme, and the contents of IgM, C3, C4, and malondialdehyde, and the expressions of pro-inflammatory genes (IL1β, IL8, IL17, and TNFα) and anti-inflammatory genes (IL4, IL10, and TGFβ1). Full-length transcriptome analysis identified 2,305 and 3,462 differentially expressed genes (DEGs) in SBM40 and FSBM40 groups, respectively. However, only 18.98% (920/5,445) of DEGs had similar expression patterns, indicating that high levels of SBM40 and FSBM40 have different metabolic strategies. KEGG enrichment analysis indicated that among the significant pathways, ~45% were related to immune diseases/systems, infectious diseases, and signal transduction in both SBM and FSBM groups. Based on PacBio SMRT sequencing, nine toll-like receptor (TLR) members, including TLR1, TLR2, TLR3, TLR5, TLR8, TLR9, TLR13, TLR21, and TLR22, were detected in intestinal tissues of pearl gentian grouper. TLR-MyD88-NF-κB signaling pathway played an important role in the development of FSBM- and SBM-induced enteritis in pearl gentian grouper; however, TLR receptors used in SBM and FSBM groups were different. TLR1, TLR8, TLR13, and TLR22 were the main receptors used in FSBM group, while TLR5, TLR8, TLR9, TLR21, and TLR22 were the main receptors used in SBM group. Present study provides valuable theoretical references for further research on soy protein-induced enteritis in fish.

Використання беззубки звичайної (Anodonta cygnea (Linne, 1758)) як добавки до рибного корму на прикладi африканського сома (Clarias gariepinus (Burchell, 1822))

Purpose. Uzbekistan aquaculture has a huge deficit of balanced feed. In a case of feed production from local ingredients, the problem is the lack of stable source of animal protein. The purpose of this experiment was to find out how swan mussel Anodonta used as a feed additive for African catfish will affect fish growth. Methodology. Minced Anodonta was prepared as follow: mussels were collected from the bottom of ponds after fish harvesting; the collected mussels were kept in the separate aquarium; every day several mussels were taken out, their shells were opened and muscle parts were separated the (mostly mussel leg); then the separated muscle were kept for disinfection in KMnO4 solution of low concentration during 20 min and then crushed to a minced state. Feed was given to African catfish according to a special scheme at the rate of 7% of the fish weight. The control group did not receive the minced mussels and fish were fed with carp feeds.The mixed feed in the experimental group #1 consisted of 50% carp feed and 50% minced mussel. In the experimental group #2, African catfish were fed with minced mussels only. Findings. The experiment showed the clear advantage of feed containing 50% of minced clams and 50% of carp feed. The African catfish fed with this feed significantly overtook fish from the control group in weight because this feed turned out to be either the most balanced in composition or better absorbed by catfish. In the control group, the 100% mixed feed gave an increase of 83.8% in weight and 20.5% in length; in the experimental group #1, the feed (50% mixed feed : 50% minced mussel) gave an increase of 136% in weight and 31.1% in length; at the experiment #2 (100% minced mussel), the feed gave an increase of 95.5% and 20.1% in length. Originality. For the first time the swan mussel was used as a source of animal protein for African catfish.This experiment was conducted for the first time, and it was also found for the first time that the addition of minced swan mussel to the feed of African catfish contributed to a significant weight gain compared to the conventional feed:52.5% more compared to conventional feed and 40.5% more compared to pure minced swan mussel. Practical value. Aquaculturenow is in search of source of animal proteinin connection with growing global deficit of a high quality fishmeal for fish feed production. Use of bivalve mollusks Anodonta, which are also a pest in pond farms, is promising feed for obtaining physiologically determined weight gains. Key words: aquaculture, Africaт catfish (Clarias gariepinus (Burchell, 1822)), feed, animal protein, plant protein, water quality, swan mussel (Anodonta cygnea (Linne, 1758)), weight gain.

Utilization of Fermented Salted Marine Trashfish Meal for Replacing Fishmeal in Nemurus Catfish (Hemibagrus nemurus) Diets

This research was carried out to determine the substitution values of fermented salted marine trash fish (FSMTF) for dietary conventional fishmeal (CFM) on growth of nemurus catfish. Four isoproteic (34% crude protein) and isocaloric (3.15 kcal DE g−1) diets were formulated. One diet was a control diet (C) in which 44% CFM was included and no FSMTF. Other three diets were test diets in which CFM was substituted with FSMTF, 50% (FSMTF-50), 75% (FSMTF-75) and 100% (FSMTF-100). A commercial diet (COM) which composed of 31 % crude protein and 2.90 kcal DE g−1 was also tested as a comparison. Nemurus catfish, 47±3.94 g in weight were distributed into triplicate net cages (2x2x1.5 m), 40 fishes per m3 water, and fed experimental diets two times daily for two months. Total substitution of fishmeal with FSMTF (FSMTF-100) in the fish diet did not affect fish growth (weight gain, specific growth rate, survival rate), feed efficiency ratio, protein efficiency ratio and protein utilization as compared to control diet. Total substitution of CFM with FSMTF gave better feed efficiency ratio, protein efficiency ratio and protein utilization than commercial diet. FSMTF therefore can completely replace CFM in the diet of nemurus catfish.

Processed by-Products from Soy Beverage (Okara) as Sustainable Ingredients for Nile Tilapia (O. Niloticus) Juveniles: Effects on Nutrient Utilization and Muscle Quality.

Simple SummaryThe consumption of soy products increases worldwide and generates large amounts of by-products, which are often discarded. Okara is a soybean by-product with high nutritional value. This work evidenced the great potential of okara meal, after appropriate technological processing, to be used as feed ingredient in Nile tilapia diets. It was clearly demonstrated the effectiveness of the autoclave and the use of proteases from C. cardunculus without fermentation to increase okara nutrient bioavailability. The inclusion of up to 20% okara meal in diets for tilapia did not affect growth performance, nutrient utilization, or whole body composition compared to a reference diet. Flesh quality remained largely unaffected, although fish fed with AOK diets had the highest density of muscle fibers.The apparent digestibility coefficients (ADCs) of differently processed okara meals were assessed in Nile tilapia diets: dried okara not autoclaved (FOK), dried okara autoclaved (AOK), okara hydrolyzed with Alcalase (ALOK) or Cynara cardunculus proteases (CYOK), and hydrolyzed okara fermented with lactic bacteria: Lactobacillus rhamnosus R11 (CYR11OK) or Bifidobacterium animalis ssp. lactis Bb12 (CYB12OK). Okara processing significantly affected nutrient digestibility: dry matter ADC was highest in CYR11OK (80%) and lowest in FOK (40%). The lowest protein digestibility was observed in CYR11OK (72%), and the highest in AOK (97%) and CYOK (91%), evidencing the effectiveness of the autoclave and the use of C. cardunculus proteases to increase okara protein bioavailability. The inclusion of up to 20% of AOK or CYOK did not affect fish growth, nutrient utilization, or whole body composition of Nile tilapia. The flesh quality (color, pH, water activity, cohesiveness, elasticity and resilience) was not affected by the dietary incorporation of AOK or CYOK. Fish fed with AOK diets stand out for their high density of muscle fibers, particularly in AOK20, which can explain their high muscle firmness and may result in further hypertrophic growth. Altogether, results suggest that hydrolyzed or autoclaved okara are valuable ingredients for Nile tilapia diets.

Dydrogesterone Affects the Transcription of Genes in Innate Immune and Coagulation Cascade in Zebrafish Embryos

Dydrogesterone (DDG) acts on the reproduction but also affects the functioning of non-reproductive system. So far, the knowledge about other effects of DDG remains limited. Here we investigated the effects of DDG on the transcription of genes in innate immune and coagulation cascade in zebrafish embryos. The zebrafish embryos were exposed to DDG at 49.0, 527 and 5890 ng L- 1 for 144 hour post fertilization (hpf). The results showed that DDG significantly decreased the transcription of marker genes (e.g. tnfa, il8 and cc-chem) involved in the innate immune response at environmental concentrations. Moreover, DDG also down-regulated the transcription of genes in coagulation cascade (e.g. fga, fgb, fgg and f2). These results indicated that DDG had potential effects on the innate immune and coagulation cascade functions in the early life zebrafish, thus further affecting fish growth and health.

Evaluation of black soldier fly (Hermetia illucens) prepupae oil as meal supplementation in diets for red hybrid tilapia (Oreochromis sp.)

Black soldier fly prepupae are a potential lipid source for aquaculture feed with high content of lipid (38.5%). In this study, the effects of black soldier fly prepupae oil (BSO) on growth performances, digestibility, fatty acid composition and hematological parameters of tilapia were investigated. Five experimental diets were formulated with Fish oil (FO) and with partial or complete (25%, 50%, 75%, or 100% BSO, respectively) replacement. The fish were fed with the diets at 5% of their body weight per day for 100 days. At the end of the experiment, tilapia from each experimental diet was individually weighed after fasting for 24 h. The results showed that FO can be successfully replaced with 25%BSO in tilapia diets without affecting fish growth performances. The highest growth (2.27%) and the lowest food conversion ratio FCR (1.39) were obtained in the fish fed with the 25%BSO diet. The BSO contained major lauric acid (35.2/100 g), palmitic acid (25.1/100 g), and oleic acid (19.6/100 g), which can be effectively utilized by tilapia. The prove that freshwater fish like tilapia can convert omega-6 to omega-3 has been shown in fish fed with BSO were higher in docosahexaenoic acid (DHA) with (6.1–7.3/100 g) than fish fed with 100% fish FO (5.7/100 g). Fish oil replacement up to 50% showed a high apparent digestibility coefficient (ADC) lipid value (90.54–95.72%). There was no palatability problem detected in this study. The values obtained for hematological parameters were within the normal ranged for tilapia. The combination of FO and 25%BSO in the diets had positive effects on red hybrid tilapia.

Determinants of Nile tilapia’s (Oreochromis niloticus) growth in aquaculture pond in Batu, Indonesia

Abstract. Lusiana ED, Musa M, Ramadhan S. 2021. Determinants of Nile tilapia’s (Oreochromis niloticus) growth in aquaculture pond in Batu, Indonesia. Biodiversitas 22: 999-1005. Nile tilapia (Oreochromis niloticus) has been commonly cultured all over the world, especially in Indonesia, due to high market demand. The success of Nile tilapia culture production depends on the fish growth during cultivation as well as pond environment. Many studies have revealed that quality of water strongly affects fish growth in an aquaculture pond. This study aims to investigate the relationship among water quality like Physico-chemical (temperature, transparency, pH, dissolved oxygen, carbon dioxide, nitrate, and phosphate) and biological (phytoplankton abundance) factors and the specific growth rate of Nile tilapia in a freshwater cultivation pond in Batu City, Indonesia. The data was analyzed using the path model. Results indicated that the most significant factor for fish growth was the phytoplankton abundance. However, since nitrate and phosphate also played roles as determinants of phytoplankton abundance, they can be considered indirect water quality factors of Nile tilapia growth.

DNA Methylation of pacap Gene Is Involved in Growth Superiority of Female Half Smooth Tongue Sole (Cynoglossus semilaevis) in Different Salinities

Pituitary adenylate cyclase activating polypeptide (PACAP) and growth hormone-releasing hormone (GHRH) play important roles in the GH/IGF growth axis in fishes. To determine whether epigenetic change is involved in the regulation of pacap and ghrh responses to low salinity stress in Cynoglossus semilaevis, the correlation between growth traits, DNA methylation status and gene expression level in low salinity (15, S15) and optimal salinity (30, S30) at day 7 (D7) and day 60 (D60) were analyzed. Results showed that exposure to low salinity for 60 days attenuated C. semilaevis growth rate. Under low salinity, DNA methylation level of pacap promoter increased in females and decreased in males at day 7, but inverted at day 60. Additionally, pacap expression was up-regulated in both males and females. The pacap promoter methylation level was higher and expression level was lower in female than in male. The results suggest that pacap promoter methylation level is negatively correlated to mRNA level and positively correlated to body weight, while gene expression level is negatively related with body weight. With the decrease of salinity, DNA methylation level of ghrh promoter and exon1, as well as its gene expression displayed minor changes. Overall, pacap gene seems to play an important role in fish growth, contributing to female growth superiority, while ghrh gene seems not pertinent under salinity stress. The results indicate that low salinity potentially affects fish growth through regulating DNA methylation in pacap promoter. This study expands the understanding of the molecular mechanism of how salinity modulates fish growth from the epigenetic perspective.

Evaluation of fermented pineapple (Ananas comosus) peel meal as a substitute for maize meal in the diet of Nile tilapia, Oreochromis niloticus

A feeding trial was conducted to investigate the effect of fermented pineapple peel meal (FPM) on Nile tilapia, Oreochromis niloticus fingerlings. One hundred and eighty (180) fingerlings of Nile tilapia (1.35±0.13g) were stocked and fed at 5% body weight per day for 56 days. Four iso-nitrogenous diets containing 35% crude protein in which corn meal was replaced by fermented pineapple peel meal at 0% (FPM0), 25% (FPM25), 50% (FPM50) and 75% (FPM75) were formulated and prepared. There was no significant difference (p>0.05) in growth, nutrient utilization, survival, protein digestibility and blood parameters between the fish fed the reference diet (FPM0) and fish fed diet FPM75. Weight gain (3.57g) was highest in fish fed diet FPM75 and lowest (2.18g) in fish fed diet FPM50. Feed conversion ratio was lowest (1.70) in fish fed diet FPM25 and highest (1.77) in fish fed diet FPM50 while protein efficiency ratio was highest in fish fed diets FPM0 (1.22) and lowest (I.03) in fish fed diet FPM50.Highest value of packed cell volume (36.33%) was in fish fed diet FPM25 while the lowest value (33.00%) was recorded in fish fed diet FPM75. From the above results therefore, yellow maize could be replaced with fermented pineapple peel meal at 75% level in the diet of Nile tilapia, Oreochromis niloticus without affecting fish growth, nutrient utilisation, protein digestibility and the blood profile.