Lipid Apparent Digestibility Coefficients Research Articles

Effects of fermented soybean meal and supplemental methionine and lysine on growth, digestibility, body composition, and amino acid composition of Beluga (Huso huso).

There is an increasing concern about using limited high-quality protein sources in the aquafeed industry. The alternative solution to this problem is cost-effective plant proteins such as soybean meal (SBM). However, it is better to improve plant protein-containing diets through processing and supplemental amino acids. This study aimed to examine the effects of fermented soybean meal (FSBM) and supplemental methionine and lysine (ML) in diets on growth, digestibility, and body and amino acid composition in Beluga (Huso huso). Two basal diets (490g FM Kg-1) of fish meal (FM) and FM with ML (FM + ML) were replaced by 40%, 60%, and 80% of FSBM and FSBM + ML (FM, FSBM40, FSBM60, FSBM80, FM + ML, FSBM40 + ML, FSBM60 + ML and FSBM80 + ML; 444g kg-1 crude protein and 19.77 MJ kg-1 gross energy). The diets were fed to triplicate groups of Beluga (394.6 ± 4.3g) three times daily for 56 d. The results showed that Beluga fed 80% FSBM and FSBM + ML had lower growth and feed utilization. Moreover, Beluga-fed FSBM + ML performed poorer than those fed FSBM (P < 0.05). No interactions between fermented SBM and ML were observed in apparent digestibility coefficients (ADC) and body proximate composition except for ADC of crude lipid. ADC in Beluga fed 80% were less than other diets. Substitution of FSBM and FSBM + ML in diets significantly reduced dry matter, ash and crude lipid; Crude lipid increased in groups fed FSBM + ML (P < 0.05). FSBM and FSBM + ML in 60% had higher and lower total amino acids in muscle and feces (P < 0.05), respectively. Also, excreted total amino acids in feces increased with ML (P < 0.05). Generally, in Beluga, FSBM-containing diets showed better effects on growth, feed utilization, whole-body lipid, and muscle and fecal amino acids than those with FSBM + ML. Fermented SBM could be replaced up to 60%.

Impacts of β‐Mannanase on Fecal Viscosity, Digestible Energy Content, Amino Acid Digestibility, and Nutrient Loss in Juvenile Nile Tilapia Fed Soybean Meal‐Rich Diets

This study evaluated the impact of increasing dietary β‐mannanase (BM) supplementation (Natupulse TS, BASF, Ludwigshafen am Rhein, Germany) on fecal viscosity and pH, apparent digestibility coefficients (ADCs) of energy and nutrients, including amino acids, fecal nutrient loss in contents of soybean meal (SBM)‐based diets fed to juvenile Nile tilapia, Oreochromis niloticus. A total of 504 fingerlings (initial body weight of 31.5 ± 4.2 g) were randomly distributed into 24 aquaria (70 L each) in a completely randomized design using six dietary treatments and four replicates of 21 fish per aquarium. Fish were fed diets containing BM at 0, 1600, 3200, 4800, 6400, and 8000 TMU (thermostable endo‐1,4‐BM units) kg−1 and hand‐fed six times a day until apparent satiety for 30 days. Chromium oxide was employed as an indigestible marker. The ADC of gross energy, crude protein, crude lipids, and essential amino acids exhibited a quadratic effect with the maximum point in fish fed 4818, 4722, 4615, and 4816 TMU kg−1 BM, respectively. The digestible energy (DE) content of diets presented a quadratic effect, and the maximum point was obtained in fish fed 4803 TMU BM kg−1 diet, which improved the DE content by +1.2 MJ kg−1 relative to the BM‐unsupplemented diet. The fecal pH, fecal viscosity, organic matter loss, and nitrogen loss presented a quadratic effect with the minimum point in fish fed 4810, 4839, 4750, and 4801 TMU BM kg−1 diet, respectively. Principal component analysis indicated that dietary BM at 4800 and 6400 TMU BM kg−1 diet was associated with improvements in the ADC of gross energy, crude protein, and crude lipids. In conclusion, including 4803 TMU BM kg−1 diet effectively improves DE content and optimizes nutrient digestibility and feces pH and viscosity in Nile tilapia fed an SBM‐based diet.

Xylanase and β-glucanase in tandem improve performance, digestive enzymes activity and digestibility in juvenile Nile tilapia fed corn distillers’ dried grains with solubles-added diet

Recently studies have demonstrated the benefits of xylanase and β-glucanase (XB) in enhancing the digestibility of nutrients in Nile tilapia (Oreochromis niloticus) fed fiber-rich diets. However, the underlying mechanisms of XB on digestive enzymes activity and growth performance are not fully understood. Therefore, this study aimed to determine the effect of XB supplementation on growth performance, blood parameters, activity of digestive enzymes, and apparent digestibility coefficients (ADC) in juvenile Nile tilapia fed corn distillers’ dried grains with solubles (DDGS)-contained diets. A 2 × 2 factorial design was used with two DDGS supplementation levels: one without DDGS (control) and one with 185 g/kg corn DDGS, either unsupplemented (−XB) or supplemented with 0.2 g/kg diet of XB (+XB). Each diet was tested using four replicates of 12 fish each. The fish (n = 192; 7.49 ± 0.07 g) were hand-fed six times daily until apparent satiety over eight weeks. DDGS inclusion improved body weight gain, energy retention efficiency, ADC of crude lipids, and digestive amylase and lipase activity. Fish fed control and DDGS diets with XB had higher feed efficiency ratio (+12.7%), energy retention efficiency (+12.5%), whole-body crude lipids (+6.5%), plasmatic cholesterol (+5.7%), activity of and lipase enzyme (+18.0%), and ADC of crude lipids (+8.8%) than those fed XB-unsupplemented diets. Exogenous XB in DDGS-contained diets increased digestible energy (DE) content by 2.22 MJ/kg, relative to values found in diet with DDGS without XB supplementation. XB improved digestible protein (DP) content by 2.9 g/kg diet relative to value found in the corresponding diets without XB supplementation. Overall, XB supplementation effectively alleviates the adverse effects of NSP in corn DDGS, enhancing digestive enzyme activity, and digestibility of energy and nutrients, thereby improving growth performance of juvenile Nile tilapia. The findings highlight the potential of corn DDGS as a sustainable and nutritive feedstuff for tilapia production.

Digestibility of Conventional and Novel Dietary Lipids in Channel Catfish Ictalurus punctatus.

Lipid and fatty acid digestibility is presumably high in Channel Catfish, but data is lacking. We determined the lipid and fatty acid digestibility of traditional and alternative dietary lipids in Channel Catfish to inform lipid choice for commercial diets. Six diets contained 4% of different lipids: soybean oil (SBO), soybean oil containing conjugated linoleic acids (CLA-SBO), catfish offal oil (COO), flaxseed oil (FXO), menhaden fish oil (MFO) and poultry fat (PF). Diets were fed to Channel Catfish (150-200 g) maintained at 26.5 °C in each of six 110 L aquaria. Six hours post-prandial, feces were collected for analysis. Total lipid, crude protein and fatty acids of lyophilized feces were analyzed, and apparent digestibility coefficients (ADCs) were calculated. ADCs of lipid, saturated and monounsaturated fatty acids, linoleic acid and protein digestibility were similar among diets. CLA isomers (cis-9, trans-11 (84.1%) and trans-10, cis-12 (90%)) in the CLA-SBO diet were highly digestible. Oleic acid digestibility was highest in the PF diet. ADC was high for α-linolenic acid in the FXO diet, and for arachidonic acid and n-3 LC-PUFA in the MFO diet. Overall, total lipid digestibility was high, but ADCs of individual fatty acids differed by source.

Mechanical processing of Phaeodactylum tricornutum and Tetraselmis chui biomass affects phenolic and antioxidant compound availability, nutrient digestibility and deposition of carotenoids in Atlantic salmon

Cell walls of microalgae differ both in terms of chemical composition and architecture. Certain characteristics of cell walls limit both the effectiveness of extraction of valuable constituents and nutrient bioavailability and bioaccessibility in fish. We first investigated the potential of bead milling to disrupt cell walls to improve extractability of bioactive compounds from Phaeodactylum tricornutum and Tetraselmis chui. We also evaluated the effect of the mechanical treatment on i) digestibility of nutrients in the two microalgae and ii) fatty acid and pigment content of fillet of Atlantic salmon fed the algae diets.Cell wall disruption facilitated efficient release of total phenolic compounds (TPC), chlorophyll A, chlorophyll B and total carotenoids from both microalgae species, but increased only the total antioxidant capacity (TAC) of T. chuii. The polyphenol profile varied between the two species; we identified 2 and 6 polyphenols from P. tricornutum and T. chui, respectively.For the feeding experiment, microalgae biomass, intact or cell wall disrupted (90.7 and 76.4% disruption degree for T. chui and P. tricornutum, respectively), were mixed with the other feed ingredients. Atlantic salmon (315 g start weight / 55 fish per tank) were fed one of the five extruded experimental diets (a fishmeal-based reference diet and four feeds with 30% of the whole or broken microalgae biomass added to the reference diet). The digestibility of protein in the P. tricornutum was significantly higher compared to that of T. chui. Breaking the cell walls by bead milling caused a significant improvement in digestibility of protein in T. chui. The apparent digestibility coefficient of lipid was higher in P. tricornutum and bead milling improved the digestibility of the two algae. However, bead milling did not favourably change the fatty acid profile of Atlantic salmon. At the end of the feeding trial, P. tricornutum-fed fish had significantly improved pigmentation, probably due to the higher content of fucoxanthin and fucoxanthinol compared to the fish fed the reference diet. The main conclusion from the mechanical processing of the microalgae is that bead milling can increase i) the extractability of polyphenols and pigments, ii) the digestibility of lipid in both algae while the effect on protein was improved only for T. chui. Furthermore, P. tricornutum can be considered a natural pigment source in the feeds of Atlantic salmon.

Dietary fishmeal replacement with Hermetia illucens (Black soldier fly, BSF) larvae meal affected production performance, whole body composition, antioxidant status, and health of snakehead (Channa striata) juveniles

Due to the market instability and increasing demand and prices of fishmeal, the aquafeed industry must seek alternative protein feedstuffs to keep producing aquafeeds in a sustainable and cost-effective way. Hermetia illucens (BSF) larvae meal is considered sustainable since its production recycles organic waste streams into a valuable nutrient. Therefore, this study assessed the effects of dietary fish meal (FM) replacement with Hermetia illucens larvae meal (HIM) on the production performance of snakehead (Channa striata) juveniles. Five isoproteic (420 g Kg−1) and isocaloric (19.5 MJ kg−1 diet) experimental diets were designed by replacing FM at 0% (control diet), 25% (HIM25), 50% (HIM50), 75% (HIM75), and 100% (HIM100) with HIM. Four hundred and fifty juveniles (16.36 ± 0.09 g fish−1) were randomly assigned to 15 tanks (400 litres; 30 fish tank−1) and fed respective diets twice daily until apparent satiety for 9 weeks. The weight gain (WG), specific growth rate (SGR), and protein efficiency ratio (PER) showed a linear decrease with increasing dietary HIM (P < 0.05), and no significant effect in fish fed control, HIM25, and HIM50 diets. Whole body proximate composition and organ somatic indices were unaffected (P > 0.05). Whole-body C12, C14, saturated fatty acid (SFA), and SFA: PUFA ratios increased linearly with increasing FM replacement whereas polyunsaturated fatty acid (PUFA) and n3/n6 fatty acid ratios decreased linearly (P < 0.05). Dietary HIM had a significant effect on protease activity (P < 0.05), but had no effect on lipase and amylase activity (P > 0.05). With increasing levels of dietary HIM, the apparent digestibility coefficient (ADC) of dry matter linearly decreased, and the ADC of crude protein showed significant linear and quadratic decrease, but the ADC of crude lipid was unaffected (P > 0.05). Aspartate aminotransferase (ASAT) and alanine aminotransferase (ALAT) were unaffected by HIM levels (P > 0.05). Fish fed HIM incorporated diets had higher superoxide dismutase (SOD) and catalase (CAT) activities than fish fed a control diet, with a linear and quadratic effect (P < 0.05). The liver glutathione peroxidase (GPx) was unaffected (P > 0.05), whereas plasma GPx increased linearly and quadratically as dietary HIM levels increased (P < 0.05). Malonaldehyde (MDA) levels in liver and plasma remained unchanged among all the groups (P > 0.05). The dietary HIM did not affect the blood biochemistry (NBT, glucose, Hb, RBC, and WBC) and plasma metabolites (total protein, albumin, globulin, and total lipids) (P > 0.05). The lower plasma cholesterol was witnessed in fish fed HIM-incorporated diets than in fish fed control diets except for the HIM50 diet (P < 0.05). In conclusion, HIM can replace dietary FM up to 50% (20 g kg−1 HIM inclusion) without harming the production performance and health of snakehead juveniles.

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.

Apparent digestibility of ten protein ingredients for largemouth bass ( Micropterus salmoides )

The study was conducted to investigate the apparent digestibility coefficients (ADC) of nutrients in commonly used protein sources for largemouth bass. A reference diet and test diets with 70% reference diet and 30% feedstuff were formulated with yttrium oxide as a digestibility indicator. Overall, the ADC of dry matter of tested protein ingredients was 69.5%–96.4%, and the ADC of dry matter in animal protein sources was significantly higher than in the other five plant protein sources. The ADC of crude proteins ranged from 89.1% to 97.3% for all tested feedstuffs. The ADC value of total amino acids in the tested ingredients is consistent with that of the protein. The ADC of crude lipid of tested ingredients ranged from 45.4% to 96.2%, and the lowest and highest values were observed in porcine haemoglobin powder and pet-grade poultry by-product meal, respectively. The ADC of total phosphorus of animal protein ingredients, except porcine haemoglobin powder, was significantly higher than that of plant protein ingredients, except fermented soybean meal. The results revealed the difference in availability of nutrients in plant and animal protein sources for largemouth bass, which could provide a theoretical basis for the selection of protein sources of commercial feed for largemouth bass.

Digestibility of Different Plant-derived Oils and their Influence on Fatty Acid Composition in the Liver and Muscle of Juvenile Common Carp (Cyprinus Carpio)

We evaluated the digestibility of plant oils and their influence on the growth of and fatty acid composition in common carp. Apparent digestibility coefficients (ADC) of lipids were determined in carp (200.2 ± 40.0g) fed with cod liver oil (CLO), linseed oil (LO), sunflower oil (SFO), or sesame oil (SO). A 96-day growth trial was then conducted using six isolipidic (from 100 to 101 g/kg diet) diets, namely CLO, LO, SFO, SO, and two blends of plant oils (SLO = SO + LO; SSFO = SO + SFO). Lipid ADC values (0.920-0.972) were similar or slightly lower in the plant oil-based diets than in the CLO-based diet. Growth and feed efficiency (FE) were not influenced by dietary lipids. The fatty acid profile in the liver and muscle reflected those of the dietary lipids. The EPA and DHA proportions were higher in the liver and muscle of the LO and SLO-fed fish than in the other plant oil groups, and lower than in CLO-fed fish (P &lt;0.05). Higher EPA, DHA, and n3/n6 ratio levels in the muscle of fish fed on the linseed oil (LO) diet, as compared to those in fish fed on the other plant oil-based diets, were ideal for human health and suggest that it can be used as a suitable alternative to fish oil.

Effects of fishmeal replacement by Clostridium autoethanogenum protein on the growth, digestibility, serum free amino acid and gene expression related to protein metabolism of obscure pufferfish (Takifugu obscurus)

A 63-day feeding trial was conducted to evaluate the effect of Clostridium autoethanogenum protein (CAP) on the growth, digestibility, postprandial free amino acid concentrations in serum, and gene expression related to protein metabolism in obscure pufferfish (Takifugu obscurus). The basal diet with 420 g/kg of fishmeal was used as the control diet (CAP0), and then 20 % (CAP20), 40 % (CAP40) and 80 % (CAP80) dietary fishmeal were replaced by CAP. Compared with diet CAP0, the growth and feed utilization was not affected in fish fed diet CAP20, but was significantly reduced in fish fed diets CAP40 and CAP80 (P < 0.05). The apparent digestibility coefficients (ADCs) of dry matter and protein in the CAP80 group were significantly lower (P < 0.05) than those of the other three groups, and the ADC of lipid was significantly decreased (P < 0.05) in the CAP40 and CAP80 groups. Fish fed diets CAP40 and CAP80 had lower taurine content in muscle compared to those fed diets CAP0 and CAP20 (P < 0.05). Higher free essential amino acid concentrations in serum were observed in fish fed diet CAP80 compared to the other diets at 2 h after refeeding (P < 0.05). Fish fed diets CAP40 and CAP80 showed lower hardness and gumminess in muscle than those fed the other diets (P < 0.05). The expression of peptide transporter1 (PepT1) in intestine and target of rapamycin (TOR) in muscle were significantly up-regulated in the CAP40 groups compared to the control (CAP0) (P < 0.05). However, relative expressions of 4F2 heavy chain (4F2hC), L-type amino acid transporter 2 (y+LAT2) and T-type amino acid transporter1(TAT1) in intestine were not significantly affected by graded levels of CAP (P > 0.05). The inclusion of CAP did not significantly affect the expression of ribosomal protein S6 kinase 1 (S6K1), eukaryotic initiation factor 4E-binding protein 1 (4E-BP1) and 4E-BP2 (P > 0.05) in muscle and liver. In summary, in a basal diet containing 420 g/kg fishmeal, 20 % fishmeal in diets could be successfully substituted by CAP, while high-level CAP decreased the growth, feed utilization and digestibility in juvenile obscure pufferfish. The main reasons for the inhibition of growth performance were probably that excessive CAP caused dietary taurine deficiency and the imbalance of amino acid absorption.

Innovative swine blood hydrolysates as promising ingredients for European seabass diets: Impact on growth performance and resistance to Tenacibaculum maritimum infection

Hydrolysates from high-protein coproducts are rich in bioactive peptides (small amino acid chains with properties beyond their nutritional value). When included in aquafeeds, they may promote fish robustness while increasing animal blood value and minimizing waste, contributing to a circular economy. This work assessed how innovatively produced blood hydrolysates (BH) included in plant-based diets for European seabass (Dicentrarchus labrax) affected growth performance and resistance to Tenacibaculum maritimum infection. Three fractions of swine BH obtained by autohydrolysis (AH) or enzymatically were selected. AH fraction was oven-dried, whilst the enzymatically obtained BH were further submitted to a micro (RMF) and nanofiltration (RNF) and the respective retentates freeze-dried. A commercially based diet was formulated, where 50% of fishmeal was replaced by vegetable proteins, and used as negative control (NC). Each BH fraction was then added at 3% to the NC and further compared to a fishmeal-based diet (positive control, PC); all diets remained isolipidic and isoproteic. Diets were assigned to triplicate groups of European seabass juveniles (12.3 ± 1.4 g) and fed three times daily until apparent satiation in a recirculating saltwater system. After a 12-week growth trial, fish were bath challenged with T. maritimum and cumulative mortality followed for 8 days. A digestibility trial was also performed in parallel. Hydrolysates-containing diets had a significantly lower apparent digestibility coefficient (ADC) of dry matter compared to the PC, but RNF did not differ from the NC. RMF and AH had lower lipid ADCs than both controls, while the RNF only differed from the PC. Mineral ADCs of PC, NC and RNF were similar. Calcium ADC in RMF and AH was significantly lower than all other diets; RMF also displayed lower copper and potassium ADCs. Fish fed PC had the highest final weight, followed by NC and RNF. Daily growth index and feed conversion ratio (FCR) of RNF was similar to both controls. RMF induced the lowest final weight, highest FCR and reduced villus length in anterior intestine. This diet has also resulted in increased plasmatic peroxidase, but lower lysozyme, compared to all other treatments, showing the lowest disease resistance. Results clearly show that the RNF was the only test diet that significantly reduced European seabass mortality after T. maritimum infection, without affecting fish growth in relation to a practical plant-protein based diet, highlighting its high potential for aquafeeds supplementation.

Apparent Digestibility of Nutrients in Thirteen Animal‐Based Feedstuffs by the Orange‐spotted Grouper Epinephelus coioides

AbstractIn this study, the apparent digestibility coefficients (ADCs) of 13 animal‐based feedstuffs were determined for a common aquaculture fish, the Orange‐spotted Grouper Epinephelus coioides. The feedstuffs included five kinds of fish meal (white fish meal [WFM]; low‐temperature‐steam‐dried brown fish meal [LTSBFM]; domestic flame‐dried fish meal; imported flame‐dried fish meal; miscellaneous fish meal [MFM]), two kinds of blood meal (spray‐dried hemoglobin meal; dried‐blood meal [DBM]), and six kinds of animal by‐product meal (chicken meal; meat and bone meal; pork meat meal; fermented feather meal [FFM]; hydrolyzed feather meal [HFM]; shrimp meal). Experimental diets were composed of reference diet at 699 g/kg, yttrium oxide at 1 g/kg (as a tracer), and each tested feedstuff at 300 g/kg. The ADCs of dry matter, crude protein, lipid, gross energy, phosphorus, and amino acids were determined for each experimental diet by the fecal sedimentation method. Overall, the ADCs of dry matter, crude protein, lipid, energy, phosphorus, and amino acids had ranges of 61.39–76.72, 72.23–91.96, 60.75–91.56, 45.20–88.45, 39.61–76.20, and 70.39–96.71%, respectively. The protein ADCs of the WFM (91.96%) and LTSBFM (91.28%) diets were significantly higher than those of the other feeds. The protein ADCs of the remaining tested diets were over 80%, except for those of the MFM, DBM, and HFM diets. The DBM and HFM diets each had the lowest and second‐lowest ADCs of crude protein, lipid, and energy. In conclusion, Orange‐spotted Grouper demonstrated high nutrient digestibility for the tested animal‐based feedstuffs except MFM, DBM, FFM, and HFM. This digestibility information can aid in the formulation of feed substitutes for least cost diets to be used with cultured Orange‐spotted Grouper.

Protein source affects apparent digestibility of feed ingredients and protein metabolism in Chinese perch ( Siniperca chuatsi )

In previous studies of apparent digestibility coefficients (ADCs), the association between apparent digestion and protein metabolism from different protein sources has long been ignored. To develop nutritionally adequate diets, this study evaluated the effects of different protein sources (fermented soybean meal [FSM], rapeseed meal [RSM], Antarctic krill powder [AKP] and fish protein hydrolysate [FPH]) on the growth performance, ADCs and expression of genes related to protein metabolism in Chinese perch. The experimental feed was composed of 300g kg-1 test ingredients and 700g kg-1 reference feed (RF). After the feeding trial, FPH was found to achieve the best growth performance of Chinese perch and had significantly higher ADCs of dry matter and gross energy than all other ingredients. Besides, FPH was the only ingredient with crude protein ADC exceeding 90% and the highest crude lipid ADC, while RSM had the lowest crude protein and crude lipid ADC. FPH showed the highest ADC of amino acids except for serine and tyrosine, and RSM showed the lowest amino acid ADC except for methionine. FPH resulted in the lowest expression of mtor, s6k, murf1, mafbx, pept2 and lat2 and the highest expression of gdh and ast in the muscle. The transcription level of cat significantly increased in the gut of the FSM group compared with that in the RF group. These findings imply that FPH may be a promising ingredient to be incorporated into the formulated diet of Chinese perch.

Apparent digestibility coefficients (ADCs) of intact-cell marine microalgae meal (Pavlova sp. 459) for juvenile Atlantic salmon (Salmo salar L.)

Initial investigations on the biochemical composition and in vitro protein digestibility indicated that dry intact-cell meals produced from Pavlova sp. CCMP strain 459 (henceforth referred to as Pav459) marine microalgae have good potential in novel low trophic aquafeeds. This study established in vivo apparent digestibility coefficients (ADCs) of essential nutrients and energy from Pav459 meal using the substitution digestion assay with juvenile (~25 g) Atlantic salmon, Salmo salar L. The Pav459 meal contained 10% ash, 54% crude protein (CP), 42 g total amino acids (AA) 100 g of meal−1, 11% crude lipid, 25% carbohydrate, 22 MJ kg−1 gross energy and 4% combined of essential n3 long chain polyunsaturated fatty acids (LC PUFA) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Pav459 meal had a high essential AA (EAA) to non-EAA ratio (1.0), EAA index (0.9), n3:n6 LC PUFA ratio (4.5), essential fatty acid (FA) index (4.9), PUFA:saturated FA ratio (2.6), fish lipid quality index (36.4) and a low index of thrombogenicity (0.1). Single ingredient Pav459 meal ADCs are established for protein (83%), lipid (91%), carbohydrate (72%) and energy (71%). Pav459 meal ADC values for EAAs are high for arginine (97%), histidine (94%), isoleucine (93%), leucine (93%), lysine (93%), methionine (95%), phenylalanine (92%), threonine (96%), tryptophan (92%) and valine (95%) and FA groupings saturates (76%), monounsaturates (80%), PUFA (97%), n6 PUFA (94%), n3 PUFA (99%) and EPA + DHA (99%). High values (average 1.8; range 1.04–3.58) are reported for the first time for Pav459 meal for digestible indispensable amino acid scores (DIAAS); which demonstrate Pav459 meal to be a complete protein when fed to Atlantic salmon. Dietary EPA + DHA levels and n3:n6 LC PUFA ratio were enhanced (by 19–31%), feed intake was significantly increased (by 8%) and carbohydrate ADC was significantly improved (by 41%) with 20% dietary Pav459 meal. Inclusion of 20% Pav459 meal had no effect on ADC of dietary dry matter, ash, monounsaturates, n3 PUFA or n6 PUFA and only trace reductions (less than 4%) for ADC of dietary protein, energy, EAAs, lipid, PUFA and EPA + DHA compared to the Reference diet. Cumulative study results suggest a recommended dietary inclusion level of Pav459 meal in salmonid feeds of up to 20% of the diet. At this level, Pav459 meal alone may satisfy NRC (2011) n3 LC PUFA requirements for Atlantic salmon and help restore EPA + DHA losses in current farmed salmon feeds; provided that similar growth performance, nutrient utilization and fish health can be demonstrated in Atlantic salmon fed nutritionally balanced diets containing Pav459 meal.

Dietary Pure Polyhydroxyalkanoate Effects on Growth, Nutrient Utilization, Apparent Digestibility, and Hematology in Nile Tilapia

AbstractIn the past decade, different groups of additives (probiotics, oligosaccharides, and plant extracts) have been widely researched and used in worldwide aquaculture. Recently, other groups, such as biopolymers (e.g., poly‐β‐hydroxybutyrate) with prebiotic properties, have been investigated. Among biopolymers, the use of pure polyhydroxyalkanoate (PHA; composition = 95–100%) as a feed additive in aquaculture has not been studied yet. Therefore, the aim of the present study was to research the effects of four supplementation levels of pure PHA on growth, survival, feed and nutrient utilization, apparent digestibility coefficients (ADCs), and hematology of Nile Tilapia Oreochromis niloticus. Five isonitrogenous and isolipidic diets were designed, including a control (C) diet without PHA supplementation. Remaining diets were supplemented with the following levels of PHA: PHA 0.1% (basal diet + 0.1% PHA), PHA 0.5% (basal diet + 0.5% PHA), PHA 1.0% (basal diet + 1.0% PHA), and PHA 2.0% (basal diet + 2.0% PHA). After a 70‐d feeding test period, the PHA 0.5% and PHA 1.0% experimental groups showed significantly higher final body weight, weight gain, specific growth rate, lipid efficiency and productive value, and ADCs of lipid and energy compared to those of the C group. Protein efficiency ratio was significantly higher in fish fed the PHA 0.1%, PHA 0.5%, and PHA 1.0% diets compared to the C group. Protein productive value significantly increased in the PHA 1.0% group. The ADC of protein was significantly higher in fish fed diets supplemented with any level of PHA compared to C fish. Regarding hematological parameters, hematocrit value showed a significant increase in fish fed PHA 0.1% compared to the C group. Leukocyte composition (%) did not show significant differences among experimental groups. Based on polynomial regression analysis, the optimum inclusion levels of PHA in Nile Tilapia diets were 0.82–0.92% for growth performance, 1.0–1.1% for nutrient utilization, 1.0–1.2% for ADCs, and 1.34% for hematocrit. Cost–benefit ratio analysis revealed nonsignificant but numerical differences among experimental diets. Results suggest that pure PHA, when supplemented at 0.1, 0.5, 1.0, or 2.0%, has certain positive effects on growth, nutrient and feed utilization, and ADCs without compromising Nile Tilapia hematology or health.

Digested soybean protein and taurine influence bile acid level, lipase activity, lipid digestibility, and growth performance of pompano (Trachinotus blochii).

This study aimed to examine the effects of dietary digested soybean protein (DSP) and taurine on bile acid (BA) level, lipase activity, lipid apparent digestibility coefficient (ADC), and growth performance of pompano (Trachinotus blochii). Five diets were formulated with fish meal (FM), defatted soybean meal (SBM), and the DSP as main dietary protein sources. The diets were denoted as follows: FMD (FM-based diet), SBMD (SBM-based diet), SBM+TD (SBM-based diet plus taurine), DSPD (DSP-based diet), and DSP+TD (DSP-based diet plus taurine). Fingerling pompano with an initial body weight (BW) of 21.4 g were stocked in 500-L tanks, with triplicate tanks per dietary treatment. For 8 weeks, the fish were hand-fed the experimental diets to apparent satiation twice daily. The results showed that the DSPD and DSP+TD groups had significantly higher final BW, weight gain, and specific growth rate, but lower feed conversion ratio, than the SBMD and SBM+TD groups, respectively (P < 0.05). There were no significant differences in growth and feed performances between fish fed DSP+TD and FMD. The gallbladder and anterior intestinal BA levels, anterior intestinal lipase activity, and lipid and protein ADCs were markedly increased in fish fed DSPD and DSP+TD compared to those fed SBMD (P < 0.05), and no significant differences were detected between the DSP+TD and FMD groups. The findings of the present study suggested that dietary DSP inclusion with taurine supplementation might effectively improve lipid digestion and this contributed to growth enhancement in pompano fed a soybean protein-based diet.

Dietary herbs supplementation improves growth, feed efficiency and apparent digestibility coefficient of hybrid grouper (Epinephelus fuscoguttatus × Epinephelus lanceolatus) juvenile

This study aimed to determine the beneficial effects of dietary herbs supplementation on hybrid grouper juveniles, a crossbreed of tiger grouper (Epinephelus fuscoguttatus) and giant grouper (Epinephelus lanceolatus). Diets of 50% protein and 12% lipid were fed to the hybrid groupers, each supplemented with 0.5% of betel leaves; BL (Piper betle), turmeric rhizomes; TR (Curcuma longa) or tuhau stems; TS (Etlingera coccinea) and a control (CON) diet for 8 weeks. The hybrid grouper juveniles were cultured in 100 L fibreglass tanks and fed twice daily. Growth performance, feed efficiency, apparent digestibility coefficient (ADC), body condition and proximate composition were observed. The highest and lowest growth rate was recorded in TR and BL respectively. However, the growth rate in TR was not significantly higher (p > 0.05) than those TS and CON. Similar results were observed in the total feed intake, feed conversion ratio, protein efficiency ratio (PER) and net protein utilization (NPU). Although BL recorded significant higher total feed intake (p < 0.05), the PER and NPU were significantly lower (p < 0.05) compared with the other groups. Body condition indices were not affected by the inclusion of TR and TS; however, significantly lower results were recorded in BL (p<0.05). The ADCs of protein and lipid were also significantly higher (p < 0.05) in TR and TS and significantly lower (p < 0.05) in BL compared with CON. The growth and feed efficiency of TR and TS supplementation were similar to CON. Nevertheless, the inclusion of these herbs increased the ADC of nutrient in the hybrid grouper.

Replacement of fish meal with defatted and fermented soybean meals in pompano Trachinotus blochii (Lacepède, 1801) diets

Abstract This study was conducted to examine the effects of the replacement of fish meal with defatted and fermented soybean meals on the growth performance, apparent nutrient digestibility, bile acid levels, and digestive enzyme activity of pompano Trachinotus blochii (Lacepède, 1801). Four diets were formulated to replace 40% of fish meal with defatted soybean meal (SBM), SBM fermented by Bacillus subtilis TH2 (FSBM1) or SBM fermented by B. subtilis B3 (FSBM2). The diets are denoted as follows: FMD (fish meal-based diet, used as a Control), SBMD (fish meal replaced by SBM diet), FSBM1D (fish meal replaced by FSBM1 diet), and FSBM2D (fish meal replaced by FSBM2 diet). Thirty fingerling pompanos with an initial body weight of 15.3 ± 0.3 g were allocated to each of eight indoor polyvinyl chloride tanks (500 L capacity), with two replicate tanks per dietary treatment. For 8 weeks, fish were hand-fed the experimental diets to apparent satiation twice daily. The final body weight, weight gain, specific growth rate, and feed conversion ratio of fish fed SBMD and FSBM1D were significantly inferior to those in fish fed FMD (P&lt;0.05). These parameters were not significantly different between the FSBM2D and FMD experimental groups (P&gt;0.05). Fish fed SBMD showed significantly lower plasma total cholesterol, whole body lipids, intestinal total bile acids and lipase activity than those fed FMD, whereas no significant differences were observed among fish fed FSBM1D, FSBM2D, and FMD. Trypsin activity and protein apparent digestibility coefficient were not significantly affected by the experimental diets. However, lipid apparent digestibility coefficient was significantly lower in fish fed SBMD and FSBM1D rather than FMD. There was no significant difference in lipid apparent digestibility coefficient between the FMD and FSBM2D experimental groups. The results indicated that SBM decreased bile acid levels, lipase activity, lipid digestibility, and growth performance in pompano fish. These parameters were increased by the inclusion of B. subtilis B3 fermented SBM in the diet, thus suggesting that fermentation of SBM with B. subtilis B3 may be an effective way to improve bile acid levels, lipase activity, lipid digestibility, and growth performance of pompano fed an SBM-based diet.

Dynamical Hybrid System for Optimizing and Controlling Efficacy of Plant‐Based Protein in Aquafeeds

In this paper, a mathematical model was used to evaluate a dynamical hybrid system for optimizing and controlling the efficacy of plant‐based protein in aquafeeds. Fishmeal (FM), raw rapeseed meal (RM), and a fermented meal with yeast (RM‐Yeast) and fungi (Aspergillus oryzae RM‐Koji) were used as test ingredients for the determination of apparent digestibility coefficients (ADCs) of dry matter, crude protein, crude lipid, energy, and essential amino acids (EAA) for olive flounder (Paralichthys olivaceus, 7 ± 0.02 g) using diets containing 0.5% Cr2O3 as an inert indicator. Among all ingredients tested, FM had the maximum ADC of dry matter (P &lt; 0.05), protein (P &lt; 0.05), lipid (P &gt; 0.05), and energy (P &gt; 0.05). Fermented meals (RM‐Yeast and RM‐Koji) showed higher ADC (P &lt; 0.05) of crude protein compared with RM, while there was no significance in ADCs of crude lipid and energy among different forms of rapeseed meal. Besides, ADC of crude lipid for RM‐Yeast and RM‐Koji, on the one hand, and ADC of gross energy for RM‐Yeast, on the other hand, were not varied from that for FM (P &gt; 0.05). Amino acid digestibility reflects protein digestibility in most cases. Interestingly, protease, lipase, and amylase activities were better expressed in RM‐Koji, RM‐Yeast, and FM over RM, respectively. The current results deliver important information on nutrients and energy bioavailability in raw and fermented RM, which can be implemented to accurately formulate applied feeds for olive flounder. Compared with other applicable systems, the complexity of the approach implemented has been considerably reduced.

Digestibility of Schizochytrium sp. whole cell biomass by Atlantic salmon (Salmo salar)

Schizochytrium sp. (Sc) is a promising nutritious and sustainable source of polyunsaturated fatty acids (PUFAs) in aquafeeds for carnivorous fish. This study investigated the apparent digestibility coefficients (ADCs) of PUFAs, along with macronutrients, other major fatty acids (FAs) and gross energy of Sc whole cells when included in diets for Atlantic salmon (Salmo salar). Thirty fish (27.9 ± 1 g) were randomly allocated to eight-120 L tanks and fed a reference or test (70% reference diet and 30% Sc biomass) diet. Over three weeks fish feces were collected by sedimentation using fecal collection columns and analyzed for digestible dry matter, gross energy, macronutrients, and FAs. ADCs of protein, lipid, and gross energy of Sc were 93.9%, 67.1% and 70% respectively. Major FAs in the Sc ingredient were palmitic acid (44.7%% FAME), docosahexaenoic acid (33.2% FAME) and docosapentaenoic acid (10.1% FAME). SFAs and PUFAs in the test diet were 15% and 7.4% higher than the reference diet, which was reflective of Sc’s FA composition. Dry matter, total lipid, gross energy and SFAs were significantly (p < 0.001) more digestible in the reference diet. PUFAs and DHA were well digested (>95%) in both diets but significantly (p = 0.038 and p < 0.001, respectively) more digestible in the test diet. This study shows that whole cell Sc offers a source of highly digestible (98%) PUFAs and protein with no need for oil extraction or cell disruption.