Digestibility Coefficients Of Crude Protein Research Articles

Methanotroph (Methylococcus capsulatus, Bath) bacteria meal alleviates soybean meal-induced enteritis in spotted seabass (Lateolabrax maculatus) by modulating immune responses and the intestinal flora

The effect of methanotroph (Methylococcus capsulatus, Bath) bacteria meal (FeedKind®, FK) supplementation in a high-soybean meal diet on growth, non-specific immunity, and gut health in spotted seabass (Lateolabrax maculatus) was investigated. Six experimental diets were formulated: control (containing 38% fish meal, FM, and 16.5% soybean meal, SBM), a high-soybean meal diet (containing 28% FM and 35% SBM), and four experimental diets each containing 28% FM and 35% SBM with the addition of FK at 2% (FK2), 4% (FK4), 6% (FK6) or 8% (FK8) in the diet to replace wheat gluten. All diets also contained 0.1% yttrium oxide to determine apparent digestibility coefficients (ADCs) of dry matter, crude protein and crude lipid. Following a 14-day acclimation period, fish were fed the diets for 56 days. Results showed that the FK2 and FK4 groups showed significantly higher weight gain (WG) compared to the SBM group (P < 0.05), whilst the FK2, FK6, and FK8 groups showed higher WG compared to the FM group (P < 0.05). The FK2, FK4, and FK8 had lower feed conversion rate (FCR) compared to the SBM group (P < 0.05). No differences were noted in overall survival. Intestinal lipase activity was significantly increased in the FK2 and FK4 groups and trypsin activity was significantly increased in the FK2 group compared to the SBM group (P < 0.05). The FK2 group showed significantly higher apparent digestibility coefficients of nutrients than the SBM group (P < 0.05). The expressions of anti-inflammatory genes (tgfβ, il-4, and il-10) in the intestine of the FK-supplemented group showed a significant increment (P < 0.05), whilst the expressions of pro-inflammatory genes (tnfα, il-1β, and il-8) significantly decreased (P < 0.05). The results of 16S rRNA gene sequencing showed that indexes of alpha diversity in the SBM group were decreased (P < 0.05) compared with all other diets. In addition, the FK2 group showed significantly higher serum acid phosphatase (ACP), alkaline phosphatase (AKP), complement 4 (C4), and total protein (TP), levels than the SBM group (P < 0.05). Inclusion of FeedKind in high SBM diets alleviated SBM-induced intestinal inflammation by modulating the expression of intestinal inflammatory factors and regulating intestinal flora. Overall, supplementation of SBM diets with 2%–4% FK improved growth, non-specific immunity, and ADC's in spotted seabass.

Comparative estimation of the lysine requirements in two generations of improved strain of Nile tilapia (Oreochromis niloticus) at the grow-out stage

A 3 × 2 factorial experiment was conducted to investigate the effects of dietary lysine on growth performance, body indices, feed intake, feed efficiency, whole body nutrient composition and amino acid deposition in two successive generations (16th and 17th) of GIFT (Oreochromis niloticus). Three diets containing different levels of lysine at 1.16%, 1.56% and 2.41% were prepared for the feeding trial. Triplicate groups of fish with an initial body weight of 155 g were fed to apparent satiation for 10 weeks in a recirculating aquaculture system. Apparent digestibility coefficients (ADC) of dry matter, crude protein, crude lipids, and total carbohydrates were measured in the experimental diets. At the end of the experiment, no interactions between dietary lysine levels in diet and fish generation were observed on all parameters except for the condition factor (CF) and ADC of crude protein. However, dietary lysine level significantly affected the final weight, weight gain, thermal unit growth coefficient (TGC), protein efficiency ratio (PER) and ADC of dry matter regardless of the fish generation. Final weight, weight gain and TGC of fish were the highest in fish fed 2.41% dietary lysine in diet or 6.52% lysine in the protein. PER was the lowest in fish fed 1.16% dietary lysine. The final weight and the body's accumulation of isoleucine, phenylalanine, and alanine were significantly affected by the fish generation, with the 17th generation having the best performance. Increase growth and higher lysine requirement observed in the improved generation (17th) compared to the (16th) generation at grow out phase indicating that genetic improvement may have changed the dietary lysine requirement.

Growth performance and quality indicators of European seabass (Dicentrarchus labrax) fed diets including refined glycerol

Glycerol is a by-product of the biodiesel industry with growing availability and applicability in animal feeds. However, its use as a source of energy in aquafeeds has only been investigated in a small number of fish species. The effects of dietary refined glycerol inclusion rate on growth performance, nitrogen and energy balances, and fish quality were investigated in juvenile European seabass. Twelve fish were assigned to each of the nine tanks and used to test the experimental diets in triplicate. The diets comprised 0, 25, or 50 g kg−1 of refined glycerol (G0, G25, and G50, respectively), being not isoenergetic, although having similar digestible protein-to-energy ratios (22 mg kJ−1). Fish were fed twice a day to apparent satiation for 90 days. The G25 group displayed a higher absolute feed intake and a higher weight gain than the G0 or G50 groups, although feed efficiency and the use of protein as an energy source were similar between the three groups. Seabass fed the G25 diet also displayed a higher specific growth rate than fish fed the G50 diet. Higher hepato-somatic and visceral lipid-somatic indices of seabass were observed with increased levels of dietary glycerol, although proximal body composition remained similar across groups. The apparent digestibility coefficients for dry matter, crude protein, and energy increased with increasing dietary glycerol inclusion rate, whereas the apparent lipid digestibility coefficient was highest for the G25 group. No differences in the energy retained as protein, nitrogen efficiency, and total ammonia excretion rate were detected between seabass fed the different diets. At the end of the growth trial, physical and microbiological quality parameters of the skin and gill surfaces were assessed after 1 and 10 days of storage on ice. Fish quality decreased with storage time but was not affected by the dietary glycerol inclusion rate. In summary, the inclusion of refined glycerol in seabass diets may have economic benefits for feed manufacture and a positive effect on growth performance but does not change the efficiency of protein utilization in this carnivorous species.

Performance and behavior of piglets fed diets with different metabolizable energy levels

This study evaluated the effect of different metabolizable energy (ME) levels in diets on digestibility, performance, and feeding behavior of weaned piglets. A digestibility study to determine ME levels was performed using 12 male piglets with 11.5 ± 0.5 kg body weight (BW), in a cross-over design fed with different ME levels (treatments). In the performance study were used 64 female piglets with 7.5 ± 0.8 kg BW, in a randomized block design with four treatments (3.30, 3.40, 3.50, and 3.60 Mcal.kg-1ME levels), and feeding program with three phases (pre-initial I, pre-initial II, and initial). For feeding behavior, four pens of each treatment were monitored with cameras. The crude-protein digestibility coefficient reduced as dietary ME level increased (P &lt;0.05). In pre-initial I animal performance was not influenced (P &lt;0.05) by ME diet levels, and in the pre-initial II and initial phases, increases in ME caused quadratic (r² 0.99) and linear (r² 0.99) effects on daily feed intake, respectively. When ME levels increased, feed conversion ratio decreased linearly in the pre-initial II phase (r² =0.98), and quadratically in the initial phase (r²= 0.99). The number and duration of feeder visits linearly decreased as the diet energy levels increased (P &lt;0.05). Weaned piglets can regulate feed intake according to dietary ME levels. The performance of weaned piglets can be maintained using diets containing metabolizable energy levels between 3.30 at 3.60 Mcal.ME.kg-1 if the ratio of nutrients to energy is maintained constant.The feed intake behavior of weaned piglets is influenced by increases in dietary metabolizable energy levels evaluated, resulting in fewer and shorter visits to the feeder.

Phytogenic blend in the diet of growing Holstein steers: Effects on performance, digestibility, rumen volatile fatty acid profile, and immune and antioxidant responses

The present study determined whether adding the phytogenic blend to the diet of growing steers would improve weight gain, the apparent digestibility of nutrients, volatile fatty acid profiles, and alter immune and antioxidant responses. The experiment included 24 Holstein calves, with an average weight of 149.6 ± 5 kg maintained in a semi-confinement system. The animals were divided into two groups (treated and control). In the concentrate of the treated group, the test product was a phytogenic blend composed of micro-encapsulated cinnamon and oregano essential oils, free turmeric extract, and tannic acid. The animals in the treated group showed more significant weight gain than the control on day 30; there was a trend toward more significant weight gain from 1 to 60 days (P = 0.07). Butyric acid concentrations were higher in the rumen, and there was an interaction between treatment and day (day 30) in the treated group. The ruminal acetic and propionic acid concentrations were higher in animals in the treated group on day 30. The intake of the phytogenic blend increased the apparent digestibility coefficient of neutral detergent fiber but did not affect the apparent digestibility coefficient of dry matter, crude protein, or mineral matter. There were significantly fewer lymphocytes in the treated group on day 30. There was a treatment effect and interaction between treatment and day for cholesterol levels, with lower levels in the treated group than in the control group. Serum glucose concentrations were lower in animals in the treated group. There was an effect of the treatment on the concentration of total proteins and globulins, with the highest levels of these proteins in the animals in the treated group. Protein electrophoresis revealed that IgA and ceruloplasmin levels showed a treatment effect and interaction, with higher levels in the treated group (P < 0.05). Heavy chain immunoglobulin levels were lower in steers in the treated group at day 90. Thiobarbituric acid reactive substance levels were lower in the treated group, indicating less lipid peroxidation (P < 0.05). We found that the levels of reactive oxygen species were lower in the treatment group at day 30, and glutathione S-transferase activity and protein thiol levels were higher in this group. These findings suggest that adding the phytogenic blend to the animals' diet was critical in the initial phase, as it modulates volatile fatty acids, stimulates immunological biomarkers, and has antioxidant activity.

ИСПОЛЬЗОВАНИЕ ПИТАТЕЛЬНЫХ ВЕЩЕСТВ РАЦИОНА ПРИ СКАРМЛИВАНИИ БЫЧКАМ КОРМОВЫХ ДОБАВОК

The article presents the results of studies on the digestibility of dietary nutrients with partial replacement of concentrated feed with protein-vitamin-mineral concentrate (PVMC) and complete replacement with compound feed concentrate (KK-65) in different periods of growing and fattening bulls for meat. The studied feed additives were used to increase the productivity of animals by enriching concentrated feed, improving the digestibility of feed nutrients. It has been established that the use of partial replacement of concentrated feed with protein-vitamin-mineral concentrate (PVMC) at 7–12 months. age and the introduction of compound feed concentrate (KK-65) instead of concentrated feed from 13 to 18 months. age in Holstein bulls had a positive effect on the digestibility of nutrients. A significant increase in the digestibility coefficients of crude protein by 2.8 %, crude fat by 1.7 % and crude fiber by 2.8 % in relation to the control group was established.

Industrial egg residue as a calcium source in broiler feed: digestibility and growth performance.

Industrial egg residue (IER) possesses substantial concentrations of calcium and crude protein. The objective of this study was to measure the digestibility and performance of broilers when IER was added to the feed. Four treatments were tested, which caused increasing replacement of calcitic limestone by IER (0, 35, 70 and 100%) during a 42-day production cycle. First, total bird excreta were collected from broilers with and without IER, and we determined dry matter digestibility, apparent metabolizable energy (AME), calcium, and nitrogen retention. The IER presented 7.5% of crude protein, 31% of calcium, 209 kcal/kg of AME and the digestibility coefficients for dry matter, crude protein, and calcium were calculated at 83.95%, 86.20%, and 67%, respectively. After the digestibility test, the effects of IER on performance, carcass and meat yield were evaluated. No significant differences between the treatments were found in terms of performance (weight gain, feed conversion, consumption, and mortality), and no differences were found in terms of carcass or meat yield. A linear decrease in the percentage of abdominal fat was observed with increasing inclusion of IER in feed. These findings suggest that IER can totally replace limestone (calcium carbonate) in broiler diets.

Use of homeopathic products in pigs feed improves the percentage, quality and marbling of meat.

Studies and innovations on alternative feed additives, especially on homeopathic remedies have been highlighted in order to replace or reduce the use of antibiotics in pig production. This paper aimed to assess the addition of homeopathic products in pig diet and their effects on the growth performance, serum metabolites, nutrient and energy digestibility, carcass traits and meat quality. A total of 60 immunocastrated male pigs, weighing on average 30.91 ± 0.95 kg, were distributed in two treatments, 10 replicates and three animals/experimental unit. There was no effect (P≥0.05) of treatment on the growth performance and serum metabolites. The percentage of acid-insoluble ash recovered in the diet was greater (P≤0.01) in diets containing homeopathic products. The apparent digestible energy of diets containing homeopathic products was reduced (P≤0.01) in the growing phase and reduced (P≤0.01) the apparent digestibility coefficients of dry matter, crude protein, soluble neutral and acid detergent fibers, and gross energy in the growing and finishing phases. Pig that received diets with homeopathic products had higher (P≤0.05) amount of meat, percentage of meat and marbling. The use of homeopathic products in diets improves the percentage and quality of meat, as well as the marbling of the pig carcass, maintaining the performance.

Phytase Supplementation under Commercially Intensive Rearing Conditions: Impacts on Nile Tilapia Growth Performance and Nutrient Digestibility

This study evaluated the effects of phytase supplementation on growth performance and apparent digestibility of Nile tilapia (Oreochromis niloticus) in a commercial fish farm setting. Nile tilapia (6300 male, 57.48 ± 1.04 g) were randomly stocked into 42 floating cages. The experimental design was completely randomized, comprising six treatments and seven replications. Fish were fed five phosphorus deficient plant-based diets with graded levels of phytase supplementation (0, 500, 1000, 1500, 2000 UF kg-1) and an additional diet containing phosphorus supplementation to meet the requirement of this fish species (positive control). After 97 days of feeding, growth performance data were collected and 900 fish (500 ± 10 g) were relocated to 6 floating cages for the digestibility assessment. Quadratic polynomial regression analysis indicated 1537.5 and 1593.2 UF kg-1 as the optimum dietary levels for daily weight gain and feed conversion rate, respectively. Including 2000 UF kg-1 resulted in the higher dry matter, crude protein, energy, and ash apparent digestibility coefficient values. Therefore, phytase supplementation from 1500 to 2000 UF kg-1 is recommended to enhance growth performance and nutrient bioavailability of Nile tilapia reared according to industry practices.

Evaluation of Six Novel Protein Sources on Apparent Digestibility in Pacific White Shrimp, Litopenaeus vannamei.

This study is aimed at evaluating the apparent digestibility coefficients (ADC) of six novel protein sources in Pacific white shrimp (Litopenaeus vannamei), including black soldier fly larvae meal (BSFLM), Chlorella vulgaris meal (CM), cottonseed protein concentrate (CPC), Tenebrio molitor meal (TM), Clostridium autoethanogenum protein (CAP), and methanotroph (Methylococcus capsulatus, Bath) bacteria meal (BPM). The control diet (CD) was formulated to contain 448.8 g/kg crude protein and 71.8 g/kg crude lipid. Then, six experimental diets were formulated to contain 70% CD and 30% test ingredients. The yttrium oxide was used as an exogenous indicator for apparent digestibility detection. Six hundred and thirty healthy and uniform-sized shrimp (approximately 3.04 ± 0.01 g) were randomly distributed into triplicate groups of 30 shrimp and they were fed three times daily. After the shrimp was acclimating for one week, their feces were collected 2 hours after the morning feeding until sufficient samples were available for compositional analysis to calculate apparent digestibility. The apparent digestibility coefficients for a dry matter of diets (ADCD) and ingredients (ADCI) as well as the apparent digestibility coefficients for crude protein (ADCPro), crude lipid (ADCL), and phosphorus (ADCP) of test ingredients were calculated. Results showed that the growth performance of shrimp fed BSFLM, TM, and BPM diets significantly decreased compared to that fed the CD (P < 0.05), and no significant differences were found among those fed CD, CM, CAP, and CPC diets (P > 0.05). There were no significant differences in survival among each group (P > 0.05). As for the diets, results showed that the ADCD of BSFLM, CM, CPC, and TM diets was significantly lower than that of CD, while that of the CAP diet was significantly higher than that of CD (P < 0.05) and there were no significant differences between BPM and CD diets (P > 0.05). As for the test ingredients, the ADCPro and ADCL of BSFLM, CM, CPC, and TM were significantly lower than those of CD in Litopenaeus vannamei (P < 0.05). The ADCPro of CAP was significantly higher than that of CD (P < 0.05), but no significant differences were found in ADCL between CAP and CD (P > 0.05). The ADCPro of BPM was significantly lower than that of CD (P < 0.05), but there were no significant differences in ADCL between BPM and CD (P > 0.05). The ADCP of CM, CAP, and BPM were significantly higher than that of CD, while that of BSFLM was significantly lower than that of CD (P < 0.05), and no significant differences were found in ADCP between TM and CD (P > 0.05). To conclude, newly developed protein sources such as single-cell protein (CAP, BPM, and CM) showed great potential as a fishmeal alternative, and insect protein meals (TM and BSFLM) were less effective for shrimp compared to the CD. Although the utilization of CPC by shrimp was lower than other protein sources, it had been much improved compared to the untreated cottonseed meal. The present study will contribute to the application of novel protein sources in shrimp feeds.

Apparent digestibility coefficients of animal feed ingredients for olive flounder (Paralichthys olivaceus)

Apparent digestibility coefficients (ADCs) of dry matter, crude protein, crude lipid, nitrogen-free extract, energy and essential amino acids in animal-based feed ingredients were determined for olive flounder (Paralichthys olivaceus). A reference diet (RF) was formulated to contain 1.0% chromic oxide (Cr2O3) as an inert indicator. Nine test diets were formulated to contain RF and one of the feed ingredients (pollock meal [PM], jack mackerel meal [JMM], anchovy meal [AM], cod meal [CM], sardine meal [SM], sand eel meal [SEM], tuna meal [TM], meat meal [MM] and squid liver meal [SLM]) at a 7:3 ratio in each diet designated as PM, JMM, AM, CM, SM, SEM, TM, MM and SLM, respectively. Olive flounder, averaging 150 ± 8.0 g, were stocked at a density of 25 fish per tank in 400-L fiberglass tanks attached with fecal collection columns. Feces were collected from triplicate groups of fish one time a day for four weeks. Dry matter and crude protein ADCs of CM and SEM were significantly higher than the other tested ingredients. Lipid ADCs of JMM, CM and SEM were significantly higher than the other test ingredients. Energy ADCs of CM and SEM were significantly higher than that of the other tested ingredients. The availability of amino acids in CM was generally higher than the other animal protein sources. PM exhibited the lowest amino acid availability among the treatments. Interestingly, MM exhibited significantly higher nutrient digestibility than several marine-based ingredients. However, CM and SEM are seeming to be highly digestible and effective to use in olive flounder diet compared to the other tested ingredients. Overall, the results of this study provide information about the bioavailability of nutrients and energy in animal feedstuffs to apply when formulating cost-effective practical feeds for olive flounder.

Effects of Zinc Oxide Nanoparticle Supplementation on Performance, Digestibility, and Blood Biochemistry of Californian Male Rabbits Under Hot Climatic Conditions.

This study aims to investigate the effects of nanoparticles of zinc oxide (Nano-ZnO) supplementation on productive performance, nutrient digestibility, mineral retention, and blood biochemistry of Californian male rabbits under hot climatic conditions. A total of 100 Californian male rabbits 90days of age (BW: 1790 ± 13g) were randomly assigned to one of five treatment diets: Nano-ZnO at 0, 25, 50, 75, or 100mg/kg, respectively, for 90days. The rabbits were raised in an open house system (average ambient temperature of 39°C, relative humidity of 30-35%, and temperature-humidity index of 33.6-34.0). Each treatment had 20 rabbits, and each rabbit was considered as a replicate. During the entire study period, there were no significant differences (P > 0.05) in BW, BW gain, feed intake, or feed conversion ratio between the treatment groups. Nano-ZnO supplementation at 25, 50, 75, and 100mg/kg enhanced the digestibility coefficient of crude protein (CP) and ether extract (EE) considerably (quadratically, P < 0.05) when compared to the control group. In addition, when Nano-ZnO was supplemented at 25, 50, 75, and 100mg/kg, serum levels of creatinine, alanine aminotransferase (ALT), and aspartate aminotransferase (AST) were considerably lower than the non-supplemented control group. Furthermore, when comparing the control and Nano-ZnO-fed rabbits, serum testosterone concentrations increased significantly (P < 0.05) in the treated groups. In addition, compared to the other groups, the 50mg/kg Nano-ZnO group had the highest cecal Lactobacilli spp. count. These findings suggest that supplementing Californian male rabbits with 50mg/kg dietary Nano-ZnO enhanced CP and EE digestibility, cecal Lactobacilli spp., as well as serum testosterone levels, and decreased serum ALT and AST levels under hot climatic conditions.

Effects of acerola (Malpighia emarginata) by-product on performance, carcass traits, antioxidant activity, and meat quality of growing rabbits

Two experiments were carried out to determine the nutritional value of acerola by-product (ABP) and the effects of dietary supply of this by-product on performance, carcass traits, biochemical parameters, antioxidant status, and meat quality of growing rabbits. In the digestibility experiment, 36 rabbits (18 males and 18 females) were allocated between 3 treatments (reference diet and two test diet, composed by 850 g/kg reference diet and 150 g/kg ABP; and 700 g/kg reference diet and 300 g/kg ABP). The ABP contained 100 g/kg crude protein (CP), 47.5 g/kg ether extract (EE), 698 g/kg neutral detergent fibre (aNDFom), 548 g/kg acid detergent fibre (ADFom), and 18.4 MJ digestible energy (DE)/kg per dry matter (DM). In the performance experiment, 120 rabbits (60 males and 60 females) were allocated in a 5 × 2 factorial design study, with five inclusion levels of ABP (0, 80, 160, 240 and 320 g/kg) and 2 genders. The regression analysis, the inclusion of ABP had a quadratic effect on final weight, daily feed intake, carcass weight, scapular fat, and overall score, with best estimated levels at 158, 265, 220, 249 and 270 g/kg, respectively (P < 0.05). ABP promoted a linear increase on the feed conversion, visceral fat, phenolic compounds in rabbit meat, antioxidant potential and total antioxidant activity (P < 0.05). ABP supply in rabbits’ diets linearly decreased the digestibility coefficients of CP, aNDFom and ADFom, cooking loss and Warner-Bratzler shear force (P < 0.05). Male rabbits had lower antioxidant potential and total antioxidant activity than female rabbits (P < 0.05). Acerola by-product enhances final weight, daily feed intake, carcass traits, meat quality, and antioxidant status of growing rabbits. Female rabbits have better antioxidant status than males.

Evaluation of growth performance, feed efficiency and nutrient digestibility of red hybrid tilapia fed dietary inclusion of black soldier fly larvae (Hermetia illucens)

Insects, particularly black soldier fly larvae (BSFM), Hermetia illucens, have been regarded as promising protein and lipid sources in animal feed, including fish. Digestibility is the key factor that affects nutrient utilization, feeding physiology and efficiency. In the present work, the effect of BSFM on the digestibility of red hybrid tilapia (RHT) compared to fish meal (FM) was ultimately unveiled. A 56-day growth trial was performed with 60 RHT (∼30 g) randomly distributed into six tanks and fed two experimental diets containing FM as a reference diet and BSFM as a test diet. In addition, faeces were collected to determine their chromium concentration and proximate composition. The apparent digestibility coefficient (ADC) of dry matter, crude protein and energy in the BSFM diet were observed to be significantly higher than those in the FM diet. Besides, the growth performance of fish fed with the BSFM diet exhibited significantly higher (P < 0.05) weight gain, specific growth rate, protein efficiency ratio and lower feed conversion ratio than those in the FM group. This study shows that the BSFM feed was well digested by tilapia and improved its growth performance.

Cassava residues in the diet of slow-growing broilers

ABSTRACT Cassava by-products are abundant and largely unused in familiy agro-industries in the Amazon region, where slow-growing broilers are commonly raised. Thus the incorporation of cassava by-products in broiler feed may provide starch enrichment for better zootechnical performance. We evaluated the use of cassava residues instead of corn in the diet of slow-growing broilers. We determined the chemical composition of cassava scrapings (CS) and cassava starch residue (CSR), and tested the digestibility of the residues in 192 broilers and three treatments: inclusion of 30 g kg-1 CS or CSR and a control without residue, with eight replicates of eight broilers each. Digestibility was assessed through collection of total excreta from 19 to 22 days of age. Apparent and corrected metabolizable energy, and apparent digestibility coefficients of dry matter, crude protein and crude energy were significantly higher for CSR than CS. Therefore, only CSR was used in a performance experiment using 324 broilers 30 to 90 days old, distributed in four treatments (0; 6.8; 13.4 and 20 g kg-1 CSR in feed) with nine replicates of nine broilers each. There was no significant difference among treatments in weight gain, feed intake, yield of carcass, breast and viscera, meat color, luminosity, pH, shear force, cooking-weight loss and drip loss. As there was a significant reduction in feed conversion and thigh and drumstick yield for 20 g kg-1, we suggest the incorporation of CSR up to 13.4 g kg-1.

Replacement of dietary fish meal with Clostridium autoethanogenum meal on growth performance, intestinal amino acids transporters, protein metabolism and hepatic lipid metabolism of juvenile turbot (Scophthalmus maximus L.)

Clostridium autoethanogenum meal (CAM) is a novel single-cell protein, which is produced from bacteria using carbon monoxide (CO) as sole carbon source. To evaluate the efficiency of CAM as an alternative for dietary fish meal, a 56-days growth experiment was performed on juvenile turbot (Scophthalmus maximus L.) with initial average weight of 9.13 ± 0.02 g. Six iso-nitrogenous (crude protein, 51.0%) and iso-lipidic (crude lipid, 11.5%) diets were formulated with 0%, 15%, 30%, 45%, 60% and 80% dietary fish meal protein substituted by CAM protein, which were designated as CAM0 (the control group), CAM15, CAM30, CAM45, CAM60 and CAM80, respectively. Results showed that no significant differences were observed in survival rate (over 97.50%) among different dietary treatments (p > 0.05). The specific growth rate (SGR) was not significantly affected when replacement levels of dietary fish meal with CAM were less than 45% (p > 0.05). The feed intake (FI) was significantly linear reduced with increasing dietary CAM (p < 0.05), whereas no significant differences were observed in feed efficiency ratio (FER), protein efficiency ratio (PER) and protein retention (PR) among different dietary treatments (p > 0.05). With increasing dietary CAM, lipid retention (LR) and carcass lipid tended to be increased in both significantly linear and quadratic patterns (p < 0.05). The apparent digestibility coefficient (ADC) of crude protein and some essential amino acids, including threonine, valine, lysine, histidine and arginine, showed significantly linear increase with increasing dietary CAM (p < 0.05). Furthermore, with the increase of dietary CAM, the gene expression of intestinal peptide and amino acids transporters was first up-regulated and then down-regulated with significantly quadratic pattern (p < 0.05), peaking in fish fed with diets CAM30 or CAM45, which was similar to the expression of genes related protein degradation in muscle. For genes related to protein metabolism in liver and muscle, the expression of mammalian target of rapamycin (mtor) was not significantly affected by dietary CAM, while the general control nonderepressible 2 (gcn2) tended to be first up-regulated and then down-regulated with significantly quadratic pattern (p < 0.05). Apart from that, the lipid metabolism of turbot was also affected by high dietary CAM, evidenced by increased expression of hepatic genes related to lipogenesis as well as reduced expression of genes related to lipid oxidation and lipid transport. In conclusion, CAM can replace up to 45% fish meal protein in diet for juvenile turbot without significantly adverse effects on growth performance. But excessive dietary CAM would result in significant growth reduction, and excessive lipid deposition may also occur in fish fed diets with high levels of CAM.

Evaluation of extruded full-fat soybean as the substitution for fish meal in diets for juvenile Scophthalmus maximus based on growth performance, intestinal microbiota, and aquaculture water quality

Extrusion technology is applied to improve the utilization of soy products, providing an alternative to fish meal (FM) as a component of feed. In this study, a 60-day feeding of turbot (Scophthalmus maximus) was conducted to evaluate the effects of the partial substitution of FM with extruded full-fat soybean (EFS) on growth performance, digestion capacities, intestinal microbiota, and aquaculture water quality. Four isonitrogenous (427.95 ± 0.38 g/kg crude protein) and isolipidic (9.80 ± 1.13 g/kg crude lipid) diets were formulated to contain FM with EFS substitution of 0% (EFS 0%), 10% (EFS 10%), 20% (EFS 20%), and 30% (EFS 30%). Each diet was fed twice a day in triplicate to juvenile turbot (initial body weight, 5.35 ± 0.07 g). The results showed that the turbot fed with EFS 30% had significantly lower body weight, specific growth rate, and protein efficiency ratio than turbot with other diets. In addition, the EFS 30% significantly decreased total serum cholesterol, low-density lipoprotein contents, intestinal folds height, and apparent digestibility coefficients of dry matter and crude protein. It also increased pathogenic Cyanobacteria at the phylum level, decreased probiotics, Rhodobacterales, and Pseudomonadales at the order level, and decreased leuconostoc and Psychrobacter at the genus level. Compared with other treatments, the EFS 30% displayed the lowest proportion of nitrogen for growth and the highest fecal nitrogen loss. Furthermore, the water quality indicators such as ammonia nitrogen discharge, total suspended solids, and fine solid accumulation (< 15 μm) reached the peak in the EFS 30% group. In conclusion, EFS is a feasible turbot feed that can substitute up to 20% of FM with no adverse effects on growth performance, digestive function, intestinal microbiota, and aquaculture water quality.

Effect of dietary soybean meal on growth performance, apparent digestibility, intestinal digestive enzyme activity and muscle growth-related gene expression of Litopenaeus vannamei

Soybean meal is one of the major components of aquatic animal diets, whereas little information is available about the evaluation of soybean meal growth suppression mode of action. A 42-day feeding trial was performed to assess the effects of dietary soybean meal on growth performance, apparent digestibility, intestinal digestive enzyme activity, and muscle growth–related gene expression of Litopenaeus vannamei. A total of 600 shrimp were randomly distributed into 20 tanks with 30 shrimp per tank and four tanks per group. The soybean meal was added to the diets at the rate of 20% (T20), 28% (T28), 35% (T35), 42% (T42), and 50% (T50), respectively. Shrimp were fed with apparent satiation three times daily. Results indicated that the final body weight, weight gain rate, specific growth rate, feed intake, intestinesomatic index, dressed weight percentage, and the apparent digestibility coefficients of dry matter, crude protein, crude lipid, and ash were linearly decreased (p &amp;lt; 0.05), but feed coefficient was linearly increased (p &amp;lt; 0.05) as dietary soybean meal increased from 20% to 50%. The intestinal trypsin and amylase activities were decreased (p &amp;lt; 0.05) as dietary soybean meal increased from 20% to 50%, and reached significance at the level of 35%, 42%, and 50%. Shrimp fed with T20 had higher (p &amp;lt; 0.05) intestinal lipase activity than those fed with other diets. The mRNA relative expression of growth hormone, myogenic regulatory factor 5, and target of rapamycin was downregulated (p &amp;lt; 0.05) as dietary soybean meal increased from 20% to 50%. To conclude, dietary soybean meal exceeded 28% significantly inhibited growth performance of L. vannamei, mainly due to the negative impact of soybean meal on digestion and feed utilization and also the inhibition on the muscle growth and related gene expressions.

Effects of exogenous xylanase supplementation in plant-based diets on growth performance, nutrient digestibility and digestive enzyme activities of juvenile mori (Cirrhinus mrigala)

The present experimental study was conducted to determine the effects of xylanase supplementation on growth performance, nutrient digestibility and digestive enzyme activities of mori, Cirrhinus mrigala. Mori with an initial body weight of 8.34 ± 0.23 g were fed seven experimental diets: a diet with high fish meal content (positive control, PC), a diet with high plant content (negative control, NC), and five other diets with increasing levels of xylanase (680, 1273, 1882, 2486 and 3091 U/kg). Each diet was fed to triplicate groups of 15 fish each for 60 days. After the trial termination, supplementation of xylanase significantly improved final weight (FW), weight gain (WG) and specific growth rate (SGR) compared to NC diet. The best feed conversion ratio (FCR) was observed at 1882 U/kg of xylanase supplementation level which was non-significant (P > 0.05) to PC diet (high fish meal content). Whole body proximate composition and apparent digestibility coefficient (ADC%) for dry matter (DM), crude protein (CP), crude fat (CF), crude ash (CA) and gross energy (GE) were significantly affected by xylanase supplementation. Activities of hepatopancreatic and intestinal amylase, protease and lipase showed an increasing trend with the increase in xylanase supplementation level, peaking at 1882 U/kg of xylanase (non-significant (P > 0.05) to PC diet) and declining thereafter (2486 U/kg-3091 U/kg). Quadratic regression analysis showed that 1948 U/kg of xylanase was the optimum value for supplementation of xylanase in plant-based diet. In conclusion, exogenous xylanase supplementation improved the growth performance, nutrient digestibility and digestive enzyme activities in juvenile mori fed plant-based diet.

Replacing soybean meal with micronized soybeans in starter piglet diets and their residual effects during growing and finishing phases

Aim of study: To assess the effects of replacing soybean meal (SBM) with micronized soybean (MS) on the digestibility (Experiment I) and performance (Experiment II) of piglets in the starter phase and its residual effects on the growing/finishing phases and carcass and meat quality traits Area of study: São Paulo, Brazil. Materials and methods: The treatments consisted of different levels of dietary replacement of SBM with MS at intervals of 25%, totaling five inclusions (0%, 25%, 50%, 75%, and 100%). Main results: In Exp. I, the administration of the pre-starter I diet resulted in a positive linear effect (p&lt;0.05) on the apparent digestibility coefficient (ADC) of crude protein and a quadratic effect (p&lt;0.01) on the ADCs of dry matter and crude fat. For the pre-starter II diet, there was a quadratic effect on the ADCs of dry matter and crude fat (p&lt;0.05). For the starter diet, a negative linear effect on the ADC of dry matter was observed (p&lt;0.01). In Exp. II, the feed intake and weight gain decreased linearly throughout the starter phase (p&lt;0.01), while no significant difference (p&gt;0.05) in feed conversion was observed with increasing inclusion level of MS. Research highlights: Replacing SBM with MS in the starter diet did not influence performance during the growing and finishing phases. Meat quality was not affected but a lower retail cut weight were observed in animals fed a starter diet with higher levels of MS.