Dietary Protein Requirement Research Articles

Dietary protein requirements of kuruma shrimp Marsupenaeus japonicas in recirculating aquaculture system

Dietary protein requirements of kuruma shrimp Marsupenaeus japonicas in recirculating aquaculture system

Effects of dietary protein levels with cottonseed protein concentrate inclusion on growth, feed utilization, liver health and intestinal microbiota of juvenile largemouth bass (Micropterus salmoides)

An 8-weeks growth trial was conducted to evaluate the effects of dietary protein levels mainly based on cottonseed protein concentrate (CPC) meal on growth performance, protein metabolism, liver health and intestinal microbiota of largemouth bass (Micropterus salmoides) juveniles. Five isolipidic (100 g/kg) diets were prepared with protein levels ranging from 400 to 560 g/kg, with CPC of 155 g/kg, 214 g/kg, 272 g/kg, 330 g/kg, 390 g/kg to obtain five experimental diets with gradient protein levels (399.9 g/kg, 428.0 g/kg, 462.8 g/kg, 503.5 g/kg and 541.5 g/kg, respectively (CPC1, CPC2, CPC3, CPC4 and CPC5)). 300 fish (initial body weight: 14.71 ± 0.50 g) were randomly assigned into 15 tanks (3 tanks per diet). The results showed that, the fish of CPC5 group had the highest specific growth rate (SGR), weight gain (WG) and feed efficiency (FE) (P < 0.05). Increased dietary protein up-regulated most liver key genes of mTOR pathway (akt, tor, s6k, 4ebp1, s6) while down-regulated atf4 at medium dietary protein (P < 0.05). The expression of fas was down-regulated with increased dietary protein, while dgat1 was higher at CPC5 group (P < 0.05). The genes related to lipolysis were up-regulated with increased dietary protein (P < 0.05). The key genes of apoptosis including bcl2, casp9, casp3 (apoptosis) oxidative stress and endoplasmic reticulum stress were significantly up-regulated at high dietary protein (P < 0.05), which reduced the antioxidant and anti-stress capacity of the liver. Dietary 462.8 g/kg protein could maintain the normal composition and metabolic function of intestinal microbiota. In summary, dietary protein requirement using CPC as main protein source was estimated to be 463 g/kg to 510 g/kg for liver health or best growth of largemouth bass juveniles.

Dietary Protein Consumption Pattern in Hyperphosphatemia Management Among Haemodialysis Patients: A Cross-Sectional Study at Kenyatta National Hospital, Kenya

Poor nutrition status in haemodialysis patients is associated with high mortality rates. A low phosphorus diet is likely to compromise dietary protein intake and nutrition status in this population. This study evaluated dietary protein consumption pattern and nutrition status among forty out-patient haemodialysis patients from Renal Unit at Kenyatta National Hospital using cross-sectional study. The Chi-square test and Kruskal‒Wallis H test were used to determine relationship between variables. More than half (58%) of the patients were male. Study participants had a mean age of 45.4±14.7 years with the majority (40%) between 40-59 years. More than three quarters (88%) had poor nutrition status with more than a third (38%) severely undernourished. More than half of the patients (53%) had dialysed for a period of more than one year. Most of study participants consumed only five types of legumes. Yellow bean, butterfly Kenyan kidney bean, butterfly haricot bean, red kidney bean and green lentil were commonly consumed legumes; 2-4 times per week by 45%, 23%, 23%, 8% and 15% of the patients respectively. Beef was the most consumed animal protein by more than half (53%) of the patients in 2-4 times a week. Second most consumed animal protein was egg white at least 2-3 times a week. Majority of the patients (58%) had poor knowledge scores (&lt;50 % score) on food phosphorus reduction food preparation procedures in protein rich foods. This study found high prevalence of poor nutrition status and inadequate consumption of dietary protein among haemodialysis patients. This study recommends nutrition education and counseling on locally available dietary proteins and their preparation in order to meet dietary protein requirements without risk of hyperphosphatemia

Dietary protein requirement of hyper-prolific sows in late gestation

Dietary protein requirement of hyper-prolific sows in late gestation

Protective effects of dietary protein against nitrite stress in grass carp (Ctenopharyngodon idella): A new perspective

Protein constitutes the predominant essential nutrient in fish feed. Despite extensive research efforts on the dietary protein of fish, limited attention has focused on its potential antistress properties. Therefore, this study sought to examine the impact of dietary protein on the liver structure of grass carp (Ctenopharyngodon idella) and its underlying molecular mechanism after nitrite stress, with the objective of elucidating the role of dietary protein in the stress response of fish. Specifically, various levels of dietary protein (16 %, 19 %, 22 %, 25 %, 28 % and 31 %) were investigated for their effects on liver tissue damage, oxidative stress, endoplasmic reticulum (ER) stress, autophagy and apoptosis in grass carp after exposure to a nitrite solution at a concentration of 10 mg/L for a duration of 96 h.Our study revealed that exposure to nitrite solution resulted in liver structural damage in grass carp. However, 22–25 % dietary protein levels might attenuate the impact of nitrite stress by decreasing liver contents of nitric oxide (NO), peroxynitrite anion (ONOO-), reactive oxygen species (ROS), protein carbonyl (PC), and malondialdehyde (MDA), which is reflected in serum activities of glutamic oxalacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT). Histological analysis further supported the protective role of appropriate protein levels (22–28 %) in alleviating nitrite-induced liver tissue damage. Subsequent investigations demonstrated that optimal dietary protein levels decreased ER stress and autophagy in fish by modulating the expression of gene and protein involved in 78 kDa glucose regulated protein (GRP78) pathway and autophagosome formation process, respectively. Meanwhile, appropriate dietary protein levels decreased the activities of caspase-3, caspase-8 and caspase-9 by inhibiting both death receptor pathway and mitochondrial pathway associated with apoptosis. Finally, based on regression analysis of liver ONOO− content, the dietary protein requirement for grass carp (721–1381 g) under nitrite stress was determined to be 25.07 %. Overall, this study provides novel evidence that optimal protein levels can enhance the resistance of grass carp to nitrite stress and mitigate liver tissue damage by reducing oxidative stress cascade damage.

Dietary protein requirement of purple mud crab, Scylla tranquebarica during the megalopa-crab instar stages

Dietary protein requirement of purple mud crab, Scylla tranquebarica during the megalopa-crab instar stages

Dietary protein intake and its association with physical fitness test among older adults with pre-sarcopenia and sarcopenia: A cross-sectional study.

Low protein intake and physical inactivity are factors that associated with muscle deterioration and poor physical performance among older adults. To assess the association between dietary protein intake and physical fitness tests among older adults with pre-sarcopenia and sarcopenia. A total of 110 older adults were recruited through a convenience sampling method. Data including sociodemography, anthropometry, body composition, medical history, and dietary protein intake were obtained through the interview-administered method. Most of the subjects have low household income (<RM 3030) (90%), Malay ethnicity (66.4%), and are married (64.5%). 74.55% of the subjects were pre-sarcopenic, whereas 25.45% were sarcopenic. Those with sarcopenia were mostly underweight (± 21.78 kg/m2), whereas those with pre-sarcopenia had a slightly higher Body Mass Index (BMI) (± 27.30 kg/m2). Both men and women did not meet the dietary protein requirement (± 43.86 g/ day) based on the Recommended Nutrient Intake (RNI) of 2017. Moreover, both pre-sarcopenic and sarcopenic subjects have reduced functional ability. Although no significant differences were found in the Short Physical Performance Battery (SPPB) score, those with sarcopenia had poorer physical performance than those with pre-sarcopenia (82.1% versus 69.5%). Apart from that, there was a significant association between the 2-min step test (2MST) and dietary protein intake among those with pre-sarcopenia (r-value = 0.252). In conclusion, lifestyle interventions among older adults are important, including ensuring adequate protein intake and encouraging appropriate physical activity to enhance muscle mass, strength, and performance to improve their daily life efficiency and quality of life.

Which Novel Ingredient Should be Considered the “Holy Grail” for Sustainable Production of Finfish Aquafeeds?

ABSTRACTThe immense production of fishmeal and fish oil is dramatically intensifying the severe state of pelagic fisheries overexploitation. The latter in conjunction with the increasing demand for low‐cost protein‐rich food supply prompt aquaculture to employ new practice. Several novel dietary ingredients are currently under evaluation for potential incorporation in aquafeeds in an effort to shift the aquaculture sector toward a more sustainable and economic production. The present review aims to summarize the existing findings regarding the effects of studied alternatives to fishmeal and fish oil on the most valuable and commercially produced marine (Sparus aurata and Dicentrarchus labrax) and freshwater (Salmo salar and Oncorhynchus mykiss) finfish species in European aquaculture. Alternative protein sources, including macroalage (marine plants), krill (marine fishery), insects (terrestrial), terrestrial animal by‐products (processed/rendered), and single cell ingredient (biotechnology), are discussed for their efficiency in promoting the growth and the welfare of both fry and adult cultured finfish species. Applicability of these ingredients is reviewed in terms of nutrient composition, dietary inclusion level, performance output, digestibility, and health benefits. In addition, a meta‐analysis was conducted based on data from peer‐reviewed scientific publications in order to assess whether novel ingredients meet the dietary protein (amino acid) and lipid requirements of finfishes. Aquafeed reformulation strategies should ensure the recommended daily nutritional requirements and additionally indicate the meta‐analysis alternatives, such as microalgae, which are deficient in essential amino acids. The sustainable expansion of aquaculture is on the horizon, but which novel ingredients may be regarded as the key drivers to its establishment?

Effects of dietary protein levels on growth performance, hemato–biochemical, and immune parameters in ship sturgeon (Acipenser nudiventris) juveniles

A feeding trial was conducted to detect the optimal dietary protein requirement for ship sturgeon (Acipenser nudiventris) juveniles. Four isoenergetic diets were formulated to contain different protein levels i.e. 40 % (P40), 45 % (P45), 50 % (P50), and 55 % (P55). A total of 180 ship sturgeon juveniles, with an average weight of 63.5 ± 1.3 g, were randomly distributed into triplicated groups (15 fish per tank) and fed on the experimental diets for 10 weeks. Significant (P < 0.05) increases in growth indices and feed intake were noted with increasing dietary protein levels up to 50 % after which (P55) fish growth was declined. The highest values of protein and lowest value of lipids and ash contents were noted in the whole-body of fish fed on the P50 diet. The levels of red blood cells, hemoglobin, and hematocrit were markedly influenced (P < 0.05) by varying dietary protein concentrations, and the most elevated values were identified in the P50 treatment. Linear increases were observed in alanine aminotransferase and alkaline phosphate levels; while quadratic increases were observed in aspartate aminotransferase activities due to the increase in dietary protein levels. Quadratic increases in total protein (TP), total immunoglobulin (total Ig), and lysozyme (LYZ) were observed due to feeding the fish on higher protein levels. The highest level of TP was significantly (P < 0.05) found in P50 and P55 with no significant (P > 0.05) difference between them. Levels of total Ig and LYZ were significantly (P > 0.05) highest in the P50 treatment. Based on the regression fitting curves of growth indices, the optimum dietary protein level for ship sturgeon (A. nutiventis) juveniles is found to be 46.5 % – 50 %. Data AvailabilityAll data of this study are included in this article.

Fat-Free Mass Derived From Bioimpedance Spectroscopy and Computed Tomography are in Good Agreement in Patients With Chronic Kidney Disease

Malnutrition is highly prevalent in patients with kidney failure. Since body weight does not reflect body composition, other methods are needed to determine muscle mass, often estimated by fat-free mass (FFM). Bioimpedance spectroscopy (BIS) is frequently used for monitoring body composition in patients with kidney failure. Unfortunately, BIS-derived lean tissue mass (LTMBIS) is not suitable for comparison with FFM cutoff values for the diagnosis of malnutrition, or for calculating dietary protein requirements. Hypothetically, FFM could be derived from BIS (FFMBIS). This study aims to compare FFMBIS and LTMBIS with computed tomography (CT) derived FFM (FFMCT). Secondarily, we aimed to explore the impact of different methods on calculated protein requirements. CT scans of 60 patients with kidney failure stages 4-5 were analyzed at the L3 level for muscle cross-sectional area, which was converted to FFMCT. Spearman rank correlation coefficient and 95% limits of agreement were calculated to compare FFMBIS and LTMBIS with FFMCT. Protein requirements were determined based on FFMCT, FFMBIS, and adjusted body weight. Deviations over 10% were considered clinically relevant. FFMCT correlated most strongly with FFMBIS (r=0.78, P<.001), in males (r=0.72, P<.001) and in females (r=0.60, P<.001). A mean difference of -0.54kg was found between FFMBIS and FFMCT (limits of agreement: -14.88 to 13.7kg, P=.544). Between LTMBIS and FFMCT a mean difference of -12.2kg was apparent (limits of agreement: -28.7 to 4.2kg, P<.001). Using FFMCT as a reference, FFMBIS best predicted protein requirements. The mean difference between protein requirements according to FFMBIS and FFMCT was -0.7±9.9g in males and -0.9±10.9g in females. FFMBIS correlates well with FFMCT at a group level, but shows large variation within individuals. As expected, large clinically relevant differences were observed in calculated protein requirements.

High protein requirements of juvenile Atlantic wolffish, Anarhichas lupus: Effects of dietary protein levels on growth, health, and welfare.

The objective of the present study was to investigate the optimal dietary protein requirement and the effect of varying protein levels on the growth and health of juvenile, wild-caught Atlantic wolffish, Anarhichas lupus, a promising candidate for cold-water aquaculture diversification. Six iso-energetic (ca. 18.3 MJ kg-1), fish meal-based experimental diets were formulated with crude protein levels ranging from 35% to 60%, with graded increments of 5% in a 12-week feeding trial in a recirculating aquaculture system (RAS). Weight gain, specific growth rate (SGR), and condition factor (K) were evaluated in response to dietary protein levels. Liver, muscle, and blood parameters were assessed for possible changes in protein and lipid metabolism and welfare. Overall growth was highly variable throughout the experiment on all diets, as expected for a wild population. The feed with highest in protein (60%) inclusion resulted in the highest growth rates, with an average weight gain of 37.4% ± 33.8% and an SGR of 0.31% ± 0.2% day-1. This was closely followed by feeds with 55% and 50% protein inclusion with an average weight gain of 22.9% ± 34.8% and 28.5% ± 38.3%, respectively, and an SGR of 0.18% ± 0.3% day-1 and 0.22% ± 0.3% day-1, respectively. Fish fed the high protein diets generally had increased hepatic lipid deposition (17%-18%) and reduced free fatty acid levels (3.1-6.8 μmol L-1) in the plasma relative to fish that were fed the lower protein diets (35%-45%). No effects of diet were found on plasma protein levels or muscle protein content. Furthermore, stress parameters such as plasma cortisol and glucose levels were unaffected by diet, as were plasma ghrelin levels. Overall, these results suggest that a high protein inclusion in the diet for Atlantic wolffish is required to sustain growth with a minimum protein level of 50%.

Dietary Protein Optimization for Growth and Immune Enhancement in Juvenile Hybrid Sturgeon (Acipenser baerii × A. schrenckii): Balancing Growth Performance, Serum Biochemistry, and Expression of Immune-Related Genes.

This study aimed to evaluate the effects of dietary protein levels on growth performance, serum indices, body amino acid composition, and intestinal gene expression in juvenile hybrid sturgeon (Acipenser baerii × A. schrenckii). Hybrid sturgeons (initial weight 29.21 ± 2.04 g) were fed isolipidic diets containing 30%, 33%, 36%, 39%, 42% or 45% crude protein for 12 weeks (n = 18 tanks, 30 fish/tank). Results showed significant differences between treatments, where weight gain and protein efficiency ratio peaked optimally between 35.9% and 38.3% dietary protein. Serum parameters such as glucose, alanine aminotransferase, aspartate aminotransferase, superoxide dismutase, and lipid peroxidation levels varied significantly with changes in dietary protein levels. Specifically, the highest enzymatic activities and growth parameters were observed in groups fed with 33% to 39% protein, enhancing whole-body concentrations of lysine, leucine, phenylalanine, proline, and glutamic acid. Immune parameters such as immunoglobulin M and lysozyme activity also showed peak levels at higher protein concentrations, particularly notable at 42% for lysozyme and 36% for both component 3 and immunoglobulin M. Gene expression related to immune and growth pathways, including MyD88, TLR1, IL-8, IL-6, NF-κB, and IL1β, was significantly upregulated at protein levels of 33% to 36%, with a noted peak in expression at 39% for TLR1, IL-10, and TOR signaling genes, before diminishing at higher protein levels. Overall, the dietary protein requirement for juvenile hybrid sturgeon ranges from 35.9% to 38.3% crude protein.

Nutritional quality and microbial diversity of Chhurpe from different milk sources: an ethnic fermented food of high-altitude regions of the Western Himalayas

Chhurpe is a naturally fermented traditional dairy food of high altitude Western Himalayan region. They are generally prepared from cow or yak milk and are consumed during harsh winters. The present study was conducted to characterize the different Chhurpe samples traditionally prepared by the ethnic groups utilizing milk from different animal breeds such as cow, yak, Zomo (cow × yak), and Germo (Zomo × yak). Nutritional characterization revealed that 100 g of Chhurpe could completely meet the dietary protein requirements of children and adults with high concentrations of methionine and lysine. Tryptophan and valine were the limiting amino acids among all the Chhurpe samples. Palmitic, stearic, and oleic acids were the predominant fatty acids. The Chhurpe samples were a rich source of micronutrients such as calcium, iron, and zinc meeting above 70% of recommended dietary allowances (RDA) among children (3–10 years) and up to 20% RDA for adults. Culture-independent metagenomic analysis revealed that lactic acid bacteria were the predominant group, consisting of genera such as Lactobacillus, Leuconostoc, Lactococcus, and Streptococcus followed by acetic acid bacteria, mainly Acetobacter. At the species level, Lactobacillus delbrueckii was the abundant strain among all the Chhurpe samples. Species diversity was significantly higher in Chhurpe prepared from Zomo milk. Probiotic bacterial strains such as Lactobacillus helveticus, L. delbrueckii, L. brevis, and Leuconostoc mesenteroides were identified in the Zomo Chhurpe indicating their superior quality. The present study was an attempt to popularize Chhurpe and promote its wider consumption by highlighting its nutritional properties.

Effects of Varying Dietary Protein Levels on Growth Performance, Survival, Body Composition, Haemato-Biochemical Profile, and Metabolic Responses of Hypselobarbus jerdoni (Day, 1870) Juveniles

A 60-day feeding trial has been carried out to access the optimal dietary crude protein (DCP) requirement of juvenile Jerdon’s carp, Hypselobarbus jerdoni. Six isoenergetic (around 400 Kcal DE/100 g), isolipidic (60.80 g/kg), and heteronitrogenous diets were prepared with graded levels of protein, viz., 200, 250, 300, 350, 400, and 450 g/kg (TCP 20-TCP 45 with 50 g/kg incremental level). A completely randomised design (CRD) was used to distribute 270 Jerdon’s carp juveniles (6.12–6.18 g) in six experimental groups in triplicates (15 fish/tank, 200 l water capacity). After 60 days, the fishes of the TCP30 group showed significantly higher weight gain, final body weight, and percentage weight gain (WG%). The fish of the TCP30 group exhibited a significantly higher feed efficiency ratio and specific growth rate. On the other hand, a significantly lower feed conversion ratio is recorded in the TCP30 and TCP35 groups. The protein efficiency ratio of fish was reduced significantly with the elevated DCP level. Whole-body moisture, lipid, and total ash contents of H. jerdoni were remain unaffected by DCP levels. However, DCP levels significantly influenced the whole-body protein of H. jerdoni juveniles, with significantly higher values noticed in the TCP30 and TCP35 groups. The TCP35, TCP40, and TCP45 groups exhibited significantly higher (p&lt;0.05) protease activity, and the amylase activity showed a decreasing trend in response to dietary protein levels. A significantly (p&lt;0.05) higher SOD and CAT activity were observed in the TCP20 and TCP25 groups. However, lower hepatic glutamate pyruvate transaminase and glutamic-oxaloacetic transaminase activity were observed in the TCP30 and TCP35 groups, respectively. Furthermore, based on broken-line linear and second-order polynomial regression with respect to WG%, the optimal dietary crude protein requirement of H. jerdoni cultured for 60 days was found to be 309.72 and 316.40 g/kg.

An estimation of optimum dietary concentration of soy bean meal for carps (Catla catla, Labeo rohita and Cirhinus mrigala).

Soybean meal is an inexpensive plant origin protein which has been used in practical diets as a replacement of animal protein such as fish meal or chicken meal, due to the uneconomical price of animal protein diets. Consequently, a research study was conducted on some commercial species of Indian major carps i.e. Catla (Cattla cattla), Rohu (Labeo rohita) and Mrigala (Cirhinus mrigala) (Hamilton, 1822) to estimate optimum dietary protein requirement of soy bean meal in diet in an intensive polyculture. Three different diets (SBM I, SBM II and SBM III) were formulated by 80%, 50% and 20% replacement of fish meal with soybean meal from a 45% fish meal diet (control).Highest monthly mean weight gain was obtained by SBM II (with 35% CP and about 50% substitution of fish meal), while SBM III (45% Crude Protein and about 20% substitution of fish meal) was stood second. All tested diets respond enormously by producing high yield as compare to control diet, though SBM II generated highest yield among all. On the bases of the following research, it was revealed that the SBM can surrogate even50% fish meal without any augmentation of other amino acids in the diet of Indian major carps.

Effects of Dietary Protein Levels on Growth, Digestive Enzyme Activity, Antioxidant Capacity, and Gene Expression Related to Muscle Growth and Protein Synthesis of Juvenile Greasyback Shrimp (Metapenaeus ensis).

An 8-week feeding trial was conducted to assess the effects on growth, antioxidant capacity, digestive enzyme activity, and gene expression related to muscle growth and protein synthesis of juvenile greasyback shrimp (Metapenaeus ensis) using five experimental diets containing 29.37%, 34.30%, 39.11%, 44.05%, and 49.32% of protein. The results demonstrated that juvenile greasyback shrimp consuming 39.11%, 44.05%, and 49.32% dietary protein had a significantly higher final body weight (FBW), weight gain (WG), feed conversion ratio (FCR), and specific growth rate (SGR) than other groups (p < 0.05). The protein efficiency ratio (PER) showed a significantly quadratic pattern with increasing dietary protein levels (p < 0.05). The highest trypsin and pepsin activities were observed in the group with a protein level of 44.05% (p < 0.05). Relatively higher superoxide dismutase (SOD) activity was found in groups with protein levels of 39.11% (p < 0.05). Alkaline phosphatase (AKP) and catalase (CAT) activity showed a significantly linear increasing pattern with increasing protein intake up to 44.05%, and then decreased gradually (p < 0.05). Compared to the dietary 29.37% protein level, the expression levels of myogenic regulatory factors (mef2α, mlc, and myf5) and mTOR pathway (mtor, s6k, akt, and pi3k)-related genes were significantly up-regulated in muscle with 39.11%, 44.05%, and 49.32% dietary protein levels (p < 0.05). The AAR pathway (gcn2, eif2α, and atf4)-related gene expression levels were significantly lower in muscles with 39.11%, 44.05%, and 49.32% protein levels than in other groups (p < 0.05). Based on the broken-line regression analysis of SGR, the estimated appropriate dietary protein requirement for juvenile greasyback shrimp is 38.59%.

Dietary effects of protein and lipid levels on growth performance and flesh quality of large-size largemouth bass (Micropterus salmoides)

The aim of this trial was to investigate the effects of dietary protein and lipid levels on growth performance and flesh quality of largemouth bass (Micropterus salmoides). A 3 × 3 two-factor design was used, including three crude protein levels of 46%, 50%, 54% (P46, P50, P54) and three crude lipid levels of 8%, 12%, 16% (L8, L12, L16). Thus, a total of nine diets (P46/L8, P46/L12, P46/L16, P50/L8, P50/L12, P50/L16, P54/L8, P54/L12 and P54/L16) were prepared and fed to large-size largemouth bass with initial body weight of 109.7 g for 84 days. At the same dietary protein level, weight gain rate (WGR), protein efficiency rate (PER), viscerosomatic index and polyunsaturated fatty acids (PUFAs) percent in flesh showed an increasing trend with increasing the dietary lipid level, while feed conversion ratio (FCR) showed a decreasing trend. At P46 and P50, whole fish crude protein, muscle crude protein, total collagen content, hardness, springiness, chewiness and shear force increased, and steaming loss and freezing loss decreased with increasing the dietary lipid level, while the above indicators showed an opposite trend at P54. At P50, the protein retention (PR) of 16% crude lipid group was significantly higher than that in the 8% and 12% crude lipid groups (P < 0.05). At the same dietary lipid level, the 50% and 54% crude protein groups presented higher WGR and lower FCR than the 46% crude protein group. The P54/L16 group had the highest WGR (184.4%) and lowest FCR (0.92) among all the groups, but the P50/L16 group presented similar WGR and FCR to the P54/L16 group (P > 0.05). The P50/L16 group showed the highest PER, PR, whole fish protein, muscle protein, total collagen, PUFAs, muscle hardness, springiness, chewiness, shear force and the lowest steaming loss. In conclusion, based on growth performance and flesh quality, the appropriate dietary protein and lipid requirements for large-size largemouth bass were 50% and 16%, respectively.

Dietary protein requirement of female climbing perch, Anabas testudineus (Bloch, 1792) broodstock

Nutritional components are multifarious amongst different producers, whereas they are just designed for fish farming but not suitable for improving the reproductive performance of brood fish. Climbing perch, Anabas testudineus is one of the candidate species for freshwater aquaculture in Asia. However, there is little knowledge available about the nutrient requirement of A. testudineus broodstock. Therefore, a feeding trial was conducted for 90-days to optimize the dietary protein requirement for reproductive performances of A. testudineus female broodstock. Six iso-energetic (around 400 Kcal digestible energy/100 g), iso-lipidic (8%) and hetero nitrogenous (25–50% crude protein, CP) semi-purified diets namely, 25% CP (T25), 30% CP (T30), 35% CP (T35), 40% CP (T40), 45% CP (T45) and 50% CP (T50) were prepared for feeding the fish of respective group twice daily. Three hundred and sixty (360) adults A. Testudineus (average body weight 18.67 ± 0.09 g) with female and male ratio of 1:1 were randomly distributed in six treatments in triplicate with the stocking density of 20 fish/ tank (500 L water volume) following a completely randomized design. Results indicated that the gonado-somatic index and viscero-somatic index increased significantly (p < 0.05) up to 40% CP then reduced gradually. But intraperitoneal fat content decreased with increasing dietary protein levels. T40 group showed lowest hepato-somatic index. The absolute fecundity was highest (p < 0.05) in 35% dietary protein fed group but found similar (p > 0.05) between T30 and T45 group. Estradiol was significantly lowest (p < 0.05) but highest 17α, 20β di-hydroxy progesterone level were observed in 35% CP fed group. Cortisol was found highest (p < 0.05) in T40, T45andT50groupand lowest in T35 group. Histological observations revealed that the females with higher proportion of vitellogenic oocytes were from 35% to 40% protein-fed groups. After induced spawning, significantly (p < 0.05) higher fecundity of spawning, rate of fertilization and hatching, and survival of larvae were observed in 40% CP fed group. Second-order polynomial regression analysis of fertilization rate (%) and larval survival (%) estimated 39.07–39.21% dietary protein is optimum for gonadal development, oocyte maturation and reproductive performance of female A. testudineus broodstock.

Evaluating the Bioremediation Capacity of the Polychaete Perinereis gualpensis (Jeldes, 1963) for Atlantic Salmon Aquaculture Sludge

The potential of polychaetes for the bioremediation of aquaculture sludge gained more attention in recent years. These organisms can reduce organic matter and nutrients contained in the sludge of several aquaculture species, improving the sustainability of these activities. The aim of this study was to evaluate the removal performance of Perinereis gualpensis (Jeldes, 1963) being fed with aquaculture sludge produced by a recirculating system cultivating Atlantic salmon. The experiment involved adding different amounts of sludge (10% and 20% with respect to total substrate) at a density of 300 organisms m−2 during 30 days. A treatment without sludge served as a control, using natural substrate. The highest removal rate of total organic matter (TOM) (23.95 ± 13.19 g m−2 day−1) was achieved by P. gualpensis with 20% sludge addition, a reduction of about 36% compared to the total amount added at the beginning of the trials. The organisms fed with aquaculture sludge presented higher nitrogen (8–9%) and carbon (40–43%) contents, with a maximum organic carbon assimilation of 32% in relation to the total content in the sludge. The high survival (88–95%) and positive growth rates (0.28% day−1) achieved by P. gualpensis indicated that this species can be sustained with salmon sludge as the only source of food. These results indicate that P. gualpensis is a promising candidate for removing nutrients from salmon effluents. Moreover, the protein contents achieved by the organisms (52–58%) meet the dietary protein requirements of several aquaculture species. Further research is needed to determine the maximum bioremediation capacity of this species and to evaluate the lipid content and fatty acid profiles of P. gualpensis to determine its potential application in aquaculture feed.

Reassessment of dietary protein and lipid requirements for large yellow croaker, Larimichthys crocea, reared in net pens

AbstractAt present, large yellow croaker, Larimichthys crocea, a carnivorous fish ranked fifth in aquaculture production among marine finfishes in the world, still relies on raw fish diet because formulated feed alone is not able to sustain rapid growth of the fish. The present study evaluated growth, feed utilization efficiency, body composition and antioxidant capacity of large yellow croaker fed diets containing four protein (430, 460, 490 and 520 g/kg) and three lipid (60, 90 and 120 g/kg) levels. Fish weighing 11.4 ± 2.8 g were fed with the test diets in net pens for 8 weeks. Final body weight and nitrogen retention efficiency (NRE) were dependent on dietary protein and lipid levels and their interaction. Weight gain, body protein content, serum catalase (CAT) activity and liver glutathione peroxidase (GSH‐Px) activity were dependent on dietary protein and lipid levels. Phosphorus retention efficiency was dependent on dietary protein level and interaction between protein and lipid levels. Hepatosomatic index, body lipid and energy contents, activities of superoxide dismutase (SOD) and GSH‐Px in serum, and CAT activity and malondialdehyde content in liver were dependent on dietary lipid level. The final body weight and weight gain of fish fed at 490 g/kg protein level did not significantly differ from those fed at 520 g/kg protein level. The final body weight, weight gain and NRE of fish fed at 90 g/kg lipid level were higher than those fed at 60 g/kg lipid level, but did not significantly differ from those fed at 120 g/kg lipid level. The maximum weight gain occurred in fish fed the diets either containing 520 g/kg protein or 90 g/kg lipid. The body lipid content, as well as SOD and GSH‐Px activities in serum, were higher in fish fed the diets with 90 and 120 g/kg lipid compared to fish fed the diets with 60 g/kg lipid. The present study reveals that the optimal dietary protein and lipid levels for large yellow croaker reared in net pens were 490–520 g/kg and 90 g/kg, respectively.