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This study was conducted to estimate the apparent digestibility coefficients (ADC) of the nutrients and energy contained in banana peel, cassava peel, cocoa husk, copra waste, and sugarcane bagasse in GIFT Nile tilapia (initial body weight 22.38 ± 0.33 g). A reference diet was formulated to satisfy the nutrient requirement of the fish. Five test diets were formulated to contain 70% of the reference diet and 30% of each test ingredient. The experiment lasted 42 days. The ADCs of dry matter (DM), crude lipid (CL), ash, crude fiber (CF), total carbohydrate (TC), and gross energy (GE) were 16.19%, 6.56%, 11.40%, 38.98% and 15.68% for banana peel; the ADCs of DM, crude protein (CP), CL, ash, CF, TC, and GE were 69.11%, 31.61%, 61.07%, 68.88%, 73.14%, 71.24%, and 69.00% for cassava peel; the ADCs of DM, ash, CF, TC, and GE were 10.56%, 0.84%, 28.70%, 2.82%, and 8.459.69% for cocoa husk; the ADCs of DM, CP, CL, ash, CF, TC, and GE were 63.08%, 20.14%, 66.60%, 32.53%, 69.70%, 66.21%, and 64.06% for copra waste; and the ADCs of DM, CF, TC, and GE were 15.22%, 36.71%, 34.34%, and 15.55% for sugarcane bagasse in tilapia respectively. This experiment generated basic information for the use of these ingredients in diet formulation for tilapia. However, considering the relatively low ADCs of nutrients observed in the present experiment, further processing could be an interesting avenue in improving the nutritional value and digestibility of these ingredients.

Two diets were formulated, a low lysine (LowL) and a balanced lysine diet (BalL), containing 9.10 and 13.10 g lysine kg−1 feed, respectively. Twenty fish (30.2 ± 1.9 g) per tank were stocked in 110-L tanks, mounted in a recycling aquaculture system (RAS), and nine hundred fish (17.2 ± 1.6 g) per pond were stocked in 200 m2 fertilized ponds (FPS). Four replicates in RAS and five replicates in FPS were assigned for each diet tested. Fish were fed with the experimental diets at a feeding rate based on metabolic body weight, twice daily for 70 days. Fish fed the BalL diet in RAS had a higher yield (kg m−3), specific growth rate, nitrogen retention efficiency (%), protein efficiency ratio (g g−1 protein), protein content and essential amino acid content, as well as a better feed conversion ratio (p .05) affect the growth indices of nutrient utilization, survival (%), body composition and essential amino acids or nitrogen utilization efficiency. Percentage compositions of plankton in the gut contents and plankton abundances in water were approximately the same between diets. The Pearson correlation coefficient (r) between plankton abundance and growth in fish fed the LowL diet was.761 and −.961 for phytoplankton and zooplankton, respectively, compared with.50 and.54 in fish fed the BalL diet. The contribution of the natural food to nitrogen gain was 30% in fish fed the LowL diet, compared with 21% in fish fed the BalL diet (p

An experiment was conducted to estimate the apparent digestibility coefficients (ADC) of macronutrients and energy of local palm kernel cakes, rice bran, maize bran and sago flour in Nile tilapia, Oreochromis niloticus (average initial body weight of 30.49 ± 0.38 g). A reference (basal) diet was formulated to contain 33% crude protein, 7% crude fat and 390 Kcal/100 g diet, all on a dry matter basis. The acid-insoluble ash was used in all the diets as the digestibility marker. The experiment lasted 37 days, including a growth phase of 28 days followed by a feces collection phase of 9 days. The results showed that the ADCs of dry matter, crude protein, crude lipid, ash, crude fiber, total carbohydrate and gross energy were 79.74%, 83.53%, 78.79%, 83.84%, 75.53%, 78.20% and 79.25% for the conventional palm kernel cake, 46.36%, 34.59%, 47.89%, 34.94%, 60.35%, 51.69% and 47.96% for refined palm kernel cake, 58.67%, 51.00%, 65.10%, 60.39%, 63.59%, 59.44% and 60.50% for rice bran, 79.24%, 94.03%, 80.34%, 99.69%, 83.83%, 76.85% and 78.61% for maize bran, and 33.74%, negative value, negative value, negative value, 8.49%, 47.65% and 35.96% for sago flour in tilapia, respectively. The present study generated original information on the digestibility of nutrients contained in these local foodstuffs, which represents a baseline, original information that could be used to formulate least-cost local feeds. However, to account for the changes in the nutrient content of these local associated with seasonality, plant variety and improvement in ingredient processing on the quality of the ingredients available on local markets, it would be interesting to collect additional samples, several times a year and run similar digestibility experiments on a regular basis, in order to have a comprehensive database that could be used by local feed miller to manufacture feed for small fish farm holders.

Agri-food system integration has the potential to increase and add value to agricultural production, reduce cost of and dependency on external inputs, generate additional income to farmers, and encourage the diversification of outputs and diets. Agri-food system integrations such as livestock-fish, poultry-fish, crop-livestock and rice-fish farming have been well documented in academic literature. However, information on fish and root, tuber and banana (RTB) crops integration is scarcely available, despite their worldwide cultural, dietary, and economic importance. This article, which is informed by a narrative literature review and ground-truthing through key informant interviews, documents existing linkages between two agri-food systems – fish and RTB – and identifies opportunities and challenges for strengthening their integration. We found that recorded instances of fish-RTB integration are limited and predominantly discuss production-related activities. Nevertheless, initial evidence suggests that there are important livelihood-enhancing opportunities as well as environmental, nutrition and food-security related benefits, which need to be considered. These include the potential to improve the nutritional status of vulnerable populations and lower the cost of fish production and thus improve the livelihoods of small-scale fish farmers. Further field-based research is recommended to explore these outcomes in more detail.

This paper reports the first benchmarking of smallholder tilapia farming practices in rural northern Zambia, measuring fish growth, feed utilization and water quality parameters, using a participatory action research approach. The effects of three different feeding regimes that are currently used in smallholder farming systems in northern Zambia on the growth of the native tilapia, Oreochromis macrochir, were tested with 15 farmers (40% female), each having three ponds (one pond per feed treatment per farmer = 45 in total), over eight months in 2016–2017. The three feed treatments included: (1) formulated feed only comprising maize and soybean; (2) goat manure only; and (3) formulated feed and manure together. Three hundred (300) O. macrochir mixed-sex fingerlings, 0.5 ± 0.1 g average weight, were stocked in each pond. Water quality (pH, dissolved oxygen, and water temperature and transparency) was measured monthly, as was fish growth in each pond by randomly sampling thirty (30) fish and taking individual weights and lengths. Results showed that the water quality parameters were broadly similar in the different feed treatments over the eight-month experiment period, except for the water transparency values that were higher in the feed only treatment when compared to the other two treatments at months four through eight. Means for survival rate, weight gain, specific growth rate, total amount of fish harvested, and yield were all higher for the feed and manure together treatment than the other two feed treatments at the end of the experiment. A linear mixed-effects regression analysis that controlled for several fixed effects and included pond as a random effect found that the feed and manure together treatment increased fish growth by 10.8 ± 3.7 g at month eight compared to the manure only treatment. The analysis also found a negative effect on fish growth (−9.4 ± 3.8 g) in ponds that used the feed only treatment. The pond effect accounted for 10.1% of the total variance in the data at month eight. Future research and development efforts in Zambia should examine more closely the factors that influence fish growth and that make up the pond effect to determine which innovations and better management practices could help smallholder farmers increase the productivity of their ponds.

This experiment investigated a blood smear method as an alternative to flow cytometry for ploidy determination in Arctic charr, Salvelinus alpinus. Fertilized eggs were either treated with hydrostatic pressure (putative triploids) or untreated (diploid controls), and the embryos, alevins, and juveniles were then reared under identical conditions. Blood samples were collected from alevins (2 g average body weight) for blood smear analysis, and from juveniles (120 g average weight) for both blood smear analysis and flow cytometry. Student's t tests revealed significant (p

A study was conducted to investigate the potential of purified lignin and hemicellulose as prebiotics in diets for Atlantic salmon, Salmo salar L., postsmolt in seawater (30 ppt) at 14.9 ± 1.2°C. T...

There is a growing concern about the use of fisheries-derived proteins in aquaculture. This study was conducted to investigate the effect of either partially or totally replacing fishmeal (up to 15% of the diet) by the inactivated dry yeast product DY-Pro in Nile tilapia Oreochromis niloticus diets. The DY-Pro replaced 0% (DY-PRO0), 2% (DY-PRO2), 5% (DY-PRO5), 25% (DY-PRO25), 50% (DY-PRO50), 75% (DY-PRO75) or 100% (DY-PRO100) of the protein provided by fishmeal in seven isonitrogenous and isocaloric experimental diets, which were fed to the experimental fish (initial average body weight 11.33 ± 1.65 g) for 12 weeks. At the end of the experiment, the graded replacement of 2–100% of fishmeal protein by the DY-Pro did not significantly (P

The effects of graded levels (0–20% total dietary inclusion) of commercial, solvent-extracted soybean meal (SBM) and expeller sunflower meal (SFM) were investigated on growth, nutrient utilization, and pro-inflammatory gene expression in the distal intestine and spleen of two commercial Canadian strains (Strain 1 and Strain 2) of Arctic charr. Five experimental diets with increasing inclusion of SBM or SFM were fed for 84 days to two Canadian strains of Arctic charr (initial body weight = 9 g/fish). Feeding these diets resulted in no differences in growth rate (measured as final weight or thermal-unit growth coefficient, TGC) in the two strains. Increased inclusion level of plant proteins negatively affected FE (P PXR gene expression in the distal intestine; PXR expression was higher with SBM than with SFM. The effect of the inclusion level of plant ingredients was significant (P IL-Iβ gene expression in the spleen. Feed intake, FE, NRE, ERE, whole body crude protein, lipid, gross energy, and organo-somatic indices were significantly (P

This article describes the sea lice control methods that are currently applicable to salmon farming in Canada. Three commercial chemical products are approved for use against sea lice in Canada: Slice®, Interox® Paramove® 50, and Calicide®. Physical control methods include photoperiod and cage-depth manipulations, desiccation of farm equipment, and the use of electric fences. Biological control measures include the polyculture of salmon with wrasse or mussel. Nutraceuticals and immunostimulants shown to reduce sea lice infestations in salmon include unmethylated DNA, yeast fermentation extract-Brewer’s yeast compound, AllBrew and NuPro, MacroGard®, and Optimun®. Salmon farmers are recommended to use site-specific integrated approaches, by properly adapting a combination of chemical, physical, biological, and nutritional measures to the environmental and financial characteristics of their farm. In the future, development of vaccines against sea lice and of salmon lines resistant to sea lice will pl...

A 2 × 3 factorial study was conducted to evaluate the effects of dietary lipid level on the expression of mitochondrial and nuclear genes involved in electron transport chain in all-female rainbow trout Oncorhynchus mykiss. Three practical diets with a fixed crude protein content of 40%, formulated to contain 10% (40/10), 20% (40/20) and 30% (40/30) dietary lipid, were fed to apparent satiety to triplicate groups of either low-feed efficient (F120, 217.66 ± 2.24 g initial average mass) or high-feed efficient (F136, 205.47 ± 1.27 g) full-sib families of fish, twice per day, for 90 days. At the end of the experiment, the results showed that there is an interactive effect of the dietary lipid levels and the phenotypic feed efficiency (growth rate and feed efficiency) on the expression of the mitochondrial genes nd1 (NADH dehydrogenase subunit 1), cytb (Cytochrome b), cox1 (Cytochrome c oxidase subunits 1), cox2 (Cytochrome c oxidase subunits 2) and atp6 (ATP synthase subunit 6) and nuclear genes ucp2α (uncoupling proteins 2 alpha), ucp2β (uncoupling proteins 2 beta), pparα (peroxisome proliferator-activated receptor alpha), pparβ (peroxisome proliferatoractivated receptor beta) and ppargc1α (proliferator-activated receptor gamma coactivator 1 alpha) in fish liver, intestine and muscle, except on ppargc1α in the muscle which was affected by the diet and the family separately. Also, the results revealed that the expression of mitochondrial genes is associated with that of nuclear genes involved in electron transport chain in fish liver, intestine and muscle. Furthermore, this work showed that the expression of mitochondrial genes parallels with the expression of genes encoding uncoupling proteins (UCP) in the liver and the intestine of rainbow trout. This study for the first time presents the molecular basis of the effects of dietary lipid level on mitochondrial and nuclear genes involved in mitochondrial electron transport chain in fish.

In aquaculture research, independent variables are qualitative (with or without a structure), quantitative, or factorial combinations. A qualitative independent variable is a variable that has unquantifiable, nominal variants (levels), which represent different categories such as the fish gender. The structure in a qualitative independent variable refers to the existence of a relation between its different variants, in a way that suggests that some variants can be grouped together and then compared to other groups of variants. A quantitative independent variable is a variable with measurable variants that are expressed numerically and are fixed throughout the experiment, such as water temperatures. In a study with one independent variable, each variant of this variable represents a treatment. In a study with two or more independent variables, also called a factorial or multifactorial experiment, the treatments represent all the possible combinations of the two or more independent variables. Following an analysis of variance (ANOVA) (or a multiple factor ANOVA) showing that there is a significant difference among the three or more treatment means, a multiple comparison test, an orthogonal contrast procedure, or a polynomial contrast procedure is applied to separate or present the relationship among the treatment means, in accordance with the nature and structure of the independent variable. The use of multiple comparison tests such as Least Significant Difference, Duncan's Multiple Range, Tukey's Honest Significant Difference, Bonferroni and Scheffe's tests, is more relevant when there is no structure in the qualitative independent variable; otherwise the use of the orthogonal contrast procedure, which allows the comparison of related treatment means or groups of means to other treatment means, is more appropriate. The orthogonal contrast procedure is also appropriate for factorial experiments. With quantitative independent variables, the use of polynomial procedure, which detects the trend of the relationship or regression that exists between the independent and response variables, is appropriate. The present paper critically analyzed the statistical methods used in articles published in ten selected international peer-reviewed aquaculture journals in the year 2013. This analysis showed that in none of the studies in which the independent variable was qualitative with a structure, the data have been analyzed using orthogonal contrast procedure. Also, the data of only 34% of the studies in which the independent variable was quantitative have been analyzed using polynomial contrast (regression), whereas the data of only 13% of studies with a factorial design have been analyzed using contrast procedure. More attention should be paid on publishing only studies that used appropriate statistical procedures, which conform to the nature of the independent variables of interest.

Good presentation of a manuscript is essential for its fast and successful editorial review. A well-written and thoroughly organized manuscript is easy to read and presents data in a manner easy to understand without a lot of repetition. Editors and reviewers are more inclined to engage with authors to improve scientific quality of well-presented manuscripts, further increasing the chances of publication. Although general approaches to scientific writing have been published, little attention has been focused on scientific writing in aquaculture research. Here, we provide students and less-experienced aquaculture researchers with some insights on research organization and manuscript presentation in order to improve their chances of getting their research into print.

A 2 × 3 factorial study was conducted to evaluate the effects of dietary lipid level on mitochondrial gene expression in mixed sex rainbow trout Oncorhynchus mykiss. Practical diets with a fixed crude protein content of 42%, formulated to contain 10% (42/10), 20% (42/20) and 30% (42/30) dietary lipid, were fed to triplicate groups of either low-feed efficient (F129; mean ± s.d. = 105.67 ± 3.04 g initial average mass) or high-feed efficient (F134; mean ± s.d. = 97.86 ± 4.02 g) families of fish, to apparent satiety, twice per day, for 108 days. At the end of the experiment, diets 42/20 and 42/30 led to similar fish condition factors, which were higher than that observed with diet 42/10 (P

A 2 × 3 factorial study was conducted to investigate the effects of dietary lipid levels on growth, feed utilization and mitochondrial enzyme activities in juvenile all-female rainbow trout ( Oncorhynchus mykiss ). Practical diets with a fixed crude protein content of 42%, formulated to contain 10% (42/10), 20% (42/20) and 30% (42/30) dietary lipid, were fed to apparent satiety to triplicate groups of either low-feed efficient (low-FE, 105.67 ± 3.04 g initial average mass) or high-feed efficient (high-FE, 97.86 ± 4.02 g) families of fish, twice per day, for 108 days. At the end of the experiment, the group of fish fed diets 42/20 and 42/30 showed higher growth and feed efficiency (FE), coupled with a lower daily feed consumption (FC), than fish fed 42/10 diet, although similar results were found with diets 42/10 and 42/30 for growth (P 0.05). The overall results of this study established that feeding a 42% CP diet with a minimum of 20% dietary lipid leads to high growth, feed utilization on the one hand, and that these zootechnical parameters are coupled with high mitochondrial enzymatic function in the liver, the intestine and the muscle of rainbow trout. Also, as it was expected, the high-FE family showed higher response to treatments than the low-FE family.

This study aimed at a simple, rapid, reliable, practical, and non-destructive sexing technique for mature zebrafish (0.61 ± 0.011 g each). In the first experiment, 36 fish of each sex were selected on the basis of the presence of a prominent genital papilla on mature females and bred randomly. All the couples laid fertilized eggs with a mean fecundity of 304 eggs per female, for a 100% sexing accuracy. In the second experiment, 140 mature zebrafish were randomly selected and individually sexed like in the first experiment. Each fish was then dissected in order to confirm the reliability of this sexing technique through the observation of either the ovaries or the testes. Upon dissection, an accuracy of 100% was recorded. This study demonstrates that sexing mature zebrafish only on the basis of the presence of a prominent genital papilla on the mature female is a reliable technique.

A 4×3 factorial experiment was conducted to evaluate the effects of two dietary protein sources (mixed fishmeal/plant protein-, and plant protein- based diet), two dietary lipid levels (10% and 20%) and three water temperatures (10°C, 14°C, and 18°C) on the growth performance, nutrient utilization efficiencies and mitochondrial enzyme complex activities in rainbow trout Oncorhynchus mykiss (average weight±SD, 39.5±5g) over a 180day rearing period. At the end of the experiment, weight gain (WG), condition factor (CF), and feed efficiency (FE) were significantly affected by diet×temperature interaction (P

A study was conducted to preliminarily assess the contribution of the intestinal microflora to biotin supply in zebrafish. Biotin and avidin were added to three isonitrogenous and isocaloric purified diets to provide molar avidin: biotin ratios of 0:0 (basal diet), 0:1 (biotin-supplemented diet), and 120:0. Another diet was made by supplementing the antibiotic succinylsulfathiazole (1%, wt/wt) to the basal diet. A fifth diet was the Zeigler commercial diet for zebrafish. Each diet was fed to a triplicate group of fish (mean initial mass 0.266 g) for 8 weeks. The condition factor, feed conversion ratio (FCR), percentage weight gain, and survival were similar in fish groups fed the commercial and the biotin-supplemented diets, but energy conversion efficiency and whole-body biotin content were highest in the fish fed the commercial diet (p0.05). Reduced growth and survival, and increased FCR were noted in fish fed basal diet compared with those fed biotin-supplemented diet. The supplementation of avidin in diet led to lower survival and condition factor, and higher FCR than that observed with basal diet. Intestinal microbial synthesis is assumed to be a significant source of biotin to the zebrafish, as fish fed the antibiotic-supplemented diet showed the lowest growth, health condition, and feed utilization.

Biotin, a water-soluble vitamin, is essential for normal growth, development and health of all animals. In terrestrial animal nutrition, biotin has recently spurred scientific interest because of the increasing body of knowledge on biotin involvement in gene expression, cell cycle and reproduction in mammals, and recent advances in molecular biology techniques allowing a more effective estimation of biotin effects in metabolism and physiology. In contrast, this information is scarce in aquatic animal nutrition, as studies have essentially focused on the estimation of minimum biotin requirement for maximum growth and tissue storage as well as for the formulation of least-cost diet. This scarcity of information is also due to the lack of well-established indicators of biotin status in aquatic organisms. The present review is a comparative analysis of current knowledge on biotin physiology and nutritional biochemistry in terrestrial and aquatic animal nutrition. Also, general information on biotin sources, bioavailability, deficiency and requirement in mammals and fish is provided in order to plan further studies. In the future, biotin nutrition studies in aquaculture should also include haematological parameters, histopathology of the gills, liver and kidney, gonad development, gamete quality and quantity, fecundity, larvae survival and gene expression. Dietary biotin requirement levels should be estimated at every life history stage of farmed fish. The potential contribution of intestinal microflora to biotin supply in different fish species should be investigated. All this information will allow a better understanding of the essentiality of biotin in fish growth, development, reproduction and health.

This study was conducted to estimate the dietary biotin requirement for maximum growth of zebrafish Danio rerio. Six isonitrogenous and isocaloric purified diets containing 0.031 (biotin-unsupplemented diet), 0.061, 0.263, 0.514, 1.741 and 2.640 mg biotin kg−1 diet were fed in triplicate tanks for a total of 12 weeks to juvenile zebrafish (initial mean body mass 0.13 ± 0.001 g). From 4 weeks of feeding, fish fed diets with ≤0.061 mg biotin kg−1 showed biotin deficiency signs, such as retarded growth and skeletal deformity, was observed on some dead fish. At the end of the study, gill disorders were observed on some fish and liver glycogen accumulation were also observed in fish fed these diets. Fish fed the biotin-unsupplemented diet exhibited a lower final body weight, protein efficiency ratio and feed utilization than the fish fed the biotin-supplemented diets, whereas the highest values were observed with the diet containing 0.51 mg biotin kg−1 diet (P