Apparent Digestibility Coefficients Of Protein Research Articles

Dried crickets (Gryllus sigillatus) or black soldier fly (Hermetia illucens) larvae meal for broiler chickens: nutrient composition and digestibility

Abstract This study explores the potential of cricket meal and black soldier fly larvae meal (BSFLM) as alternative protein sources in broiler chicken diets. With the use of the substitution method, using diatomaceous earth as an external marker, we investigated the nutrient availability and apparent metabilizeable energy content of oven-dried full-fat cricket meal (OD-CM), freeze-dried full-fat cricket meal (FD-CM), and defatted BSFLM in a feeding trial involving 320 Ross 308 broilers housed in 32 pens (8 replicates / treatment; 8 birds / pen). Feed intake, daily weight gain, and feed conversion ratio were measured between days 15 and 21. Excreta collected on days 19, 20, and 21 were analyzed for nutrient content. Both cricket treatments were high in crude protein. Additionally, FD-CM demonstrated the highest fat content, surpassing OD-CM. OD-CM displayed a significantly higher apparent digestibility coefficient for crude protein compared to BSFLM (). FD-CM had the highest apparent digestibility coefficient for gross energy (). The nitrogen-corrected apparent metabolizable energy of OD-CM and FD-CM were significantly higher than that of BSFLM (). Furthermore, OD-CM exhibited a significantly higher available crude protein content compared to BSFLM and FD-CM (). This research sheds light on the potential of OD-CM and FD-CM as valuable alternative protein sources for broiler chickens, providing critical insights for the poultry industry’s sustainable future. This research is important as the apparent digestibility coefficients, as well as available nutrients calculated for the three ingredients may be used to accurately formulate poultry diets on an available nutrient basis.

Solid-state fermentation converts rice bran into a high-protein feed ingredient for Penaeus monodon

Fermented rice bran (FRB) was evaluated as an alternative protein source to soybean meal (SM) in practical diets for juvenile black tiger shrimp, Penaeus monodon. This feed ingredient was tested in a feeding trial to replace soybean meal in P. monodon diets at 0% (T0), 12.5% (T12.5), 25% (T25), 37.5% (T37.5), and 50% (T50). Five iso-nitrogenous and iso-caloric experimental diets containing 44% crude protein were fed to groups of juvenile shrimp (0.47 ± 0.002 g) randomly assigned to twenty 60-l rectangular tanks equipped with a recirculating seawater system. Each dietary treatment was run in 4 replicates, and the feeding trial lasted 50 days. Results show significant improvement in weight gain, specific growth rate, and protein efficiency ratio in treatment T12.5 and T25. Treatments with higher levels of SM replacement with FRB exhibited similar growth indices to those of the control group. Polynomial regression analysis indicates that the optimum replacement of soybean meal with FRB for optimum growth is 21.08%. The apparent dry matter and protein digestibility coefficients of FRB are 83.05 ± 0.02% and 87.20 ± 0.30%, respectively. There were no significant differences in the whole-body composition (dry matter, protein, lipid, ash) among treatments of shrimp fed with FRB replacement. The data suggest that FRB replacement of dietary soybean meal is feasible at 50% without affecting the growth performance but may promote growth at 21.08% replacement of P. monodon.

Nutrient Digestibility of Non-conventional Protein Sources Blend in African Catfish, Clarias gariepinus (Burchell, 1822) Post Juveniles Using Novel Aquafeed Formulation Software

In this study, the growth performance, carcass composition, and apparent digestibility coefficient of African catfish, Clarias gariepinus, were evaluated in relation to different non-conventional protein sources blends diets that were formulated using a novel feed formulation software (FUTA AQUAFEED). Diet 1 served as the control diet, and the other four experimental diets (Diets 2 through 5) included non-conventional protein sources such blood meal, water hyacinth, palm kernel cake, palm beetle meal, blackfly meal, water fern, and Moringa. The gross composition of the experimental feeds exhibited notable variations in nutrient content. The crude protein content in the diets were iso-nitrogenous. Analysis of the composition of the carcass showed that diets varied significantly. Diet 5 had the highest fat content (10.66%), while Diet 3 had the highest crude protein amount (61.57%). Growth performance parameters such as initial and final weights, weight increase, feed conversion ratio (FCR), specific growth rate (SGR), and protein efficiency ratio (PER) exhibited diverse patterns. Diet 5 produced the greatest final weight (324.00 ± 122.94 g) and weight gain (173.32 ± 96.06 g), suggesting that the varied protein blend may have advantages. Dietary differences were seen in the apparent digestibility coefficients of crude protein and lipids. The crude protein digestibility coefficient (90.68%) was best in Diet 3, while the crude lipid digestibility coefficient (92.00%) was highest in Diet 1. In conclusion, the inclusion of unconventional protein sources in the diets of C. gariepinus affects both their growth performance and nutritional makeup. Through the incorporation of alternate protein sources into fish diets, the findings offer insights for improving aquaculture techniques and advancing sustainability.

Maintenance requirement and growth utilization efficiency of digestible methionine and cysteine determined for striped catfish (Pangasianodon hypophthalmus) using ration level technique

Knowledge of the amino acid (AA) requirements for striped catfish (Pangasianodon hypophthalmus) is very limited. The main objective of the study was to determine maintenance requirements and utilization of digestible methonine (Met) and other essential amino acids (EAA) for growth in juvenile striped catfish. To evaluate the objective, a series of three different trials were carried out. Initially, a 28-d feed deprivation study showed an allometric relationship between energy, protein, or AA losses (y) and geometric body weight (BW), where the relationship was expressed as a power function (y = aBWb) with the exponent values (b) being 0.84 for energy, 0.83 for protein, and 0.81–0.90 for various EAAs. Next, a digestibility trial was carried out to determine apparent digestibility coefficients of energy, protein and AA from the ingredients, including: fish meal, soybean meal, wheat bran, regular and defatted rice bran. These values were then used in the final trial to formulate two diets on a digestible AA basis with similar crude protein (31%), energy (17.1 kJ g−1) and AA composition - except for digestible Met and Met+Cys, which were 0.47% and 0.90% for Diet A, and 0.61% and 1.05% for Diet B. The diets were fed to quadruplicate groups of fish (∼10 g initial weight; 20 fish per tank) at increasing ration levels (∼ 35%, 55%, 77%, 93% and 100% apparent satiation) for 64 days. One group was deprived of feed for 28 days. The results showed that feeding catfish at increasing ration levels significantly improves the growth performance in both dietary treatments. Additionally, the group fed Diet B showed significantly better weight gain than the corresponding group fed Diet A at 93% and 100% satiation. The maintenance requirement was determined to be 21.77 mg digestible (dig) Met kg−0.83 d−1 and 35.3 mg dig Met+Cys kg−0.83 d−1 based on a linear model and to be 18.8 mg digestible (dig) Met kg−0.83 d−1 and 30.7 mg dig Met+Cys kg−0.83 d−1 based on an exponential fit to the data. The efficiency of digestible Met utilization (kDMetassessed based on Diet B) for growth above maintenance was found to be 63% (including data of all ration levels) or 71% (excluding data of 100% satiation), while that for the Met+Cys (kDM+C) was found to be 46% (including data of all ration levels) or 51% (excluding data of 100% satiation). The efficiency of digestible protein utilization for weight gain with Diet B was found to be higher (66%) than that with Diet A (57%), indicating the importance of balancing striped catfish diets for dietary Met. The study also determined maintenance requirements and utilization efficiency of other EAAs which need to be further improved. These data can be used to derive AA requirements for striped catfish based on a factorial modelling approach which relies on maintenance requirements, growth utilization of AA, and targeted growth or protein deposition.

Effects of the Replacement of Dietary Fishmeal by the Blend of Tenebrio molitor Meal, Chlorella Meal, Clostridium Autoethanogenum Protein, and Cottonseed Protein Concentrate on Growth, Protein Utilization, and Intestinal Health of Gibel Carp (Carassius gibelio, CAS Ⅴ)

The trial was conducted to investigate the effects of the replacement of dietary fishmeal (FM) by the blend of Tenebrio molitor meal (TMM), Chlorella meal (CM), Clostridium autoethanogenum protein (CAP), cottonseed protein concentrate (CPC) on growth, protein utilization and intestinal health of gibel carp (Carassius gibelio, CAS Ⅴ). The FM-based diet was used as the control, and the blended proteins (TMM: CM: CAP: CPC) at ratios of 1 : 1:8 : 2 (BLEND A), 1 : 1:6 : 4 (BLEND B), and 1 : 1:4 : 6 (BLEND C) were used to replace FM at three levels (33%, 67%, 100%), respectively. The results showed that, compared to the control group, growth performance increased significantly when dietary FM was fully replaced by BLEND B (P<0.05), while decreased by BLEND A (P<0.05). The complete substitution of FM with BLEND B significantly upregulated the mRNA expression of intestinal proinflammatory cytokines, anti-inflammatory cytokines, and tight junction-related genes (P<0.05), improving intestinal tissue morphology and health. And it also significantly increased intestinal trypsin activity (P<0.05), upregulated the mRNA expression of amino acid sensory receptor-related and amino acid or peptide transport-related genes (P<0.05), increased protein apparent digestibility coefficient (P<0.05). The 100% substitution of FM with BLEND A significantly upregulated the mRNA expression of intestinal proinflammatory cytokines and downregulated the mRNA expression of anti-inflammatory cytokine il-10 (P <0.05), reduced intestinal villus height (P<0.05), and decreased protein apparent digestibility coefficient (P<0.05). In conclusion, BLEND B could completely substitute dietary FM and was beneficial to the growth and health of gibel carp. Dietary digestible essential amino acids index (DEEAI) was found as an important indicator and should be higher than 79.5% to meet the maximum growth of fish.

Exploring the nutritional value of corn fermented protein as a replacement for soybean meal in diets for juvenile channel catfish (Ictalurus punctatus): Impacts on production performance, intestinal health, and disease resistance

The use of corn fermented protein (CFP) can be a promising alternative ingredient to replace soybean meal (SBM) in aquafeeds, because of its attractive price and constant supply. In this study, the apparent digestibility of CFP was evaluated with channel catfish (Ictalurus punctatus), followed by a comparative feeding trial in which dehulled, solvent extracted SBM in the control diet was incrementally replaced with graded levels of CFP. A slight but significantly higher apparent protein digestibility coefficient was observed for SBM (91%) compared to CFP (89%). However, phosphorus and lipid were twice as available from CFP than SBM. A 60-day feeding trial was conducted, testing the gradual replacement of SBM by CFP on an equalnitrogen basis at 0, 25, 50, 75, and 100%. Channel catfish juveniles (∼11.6 g) were stocked in 30 aquaria (30 fish/ 110-L tank; n = 6) operating as a recirculating system and offered the experimental diets to apparent satiation twice daily. No differences were observed for hepatosomatic index, survival, or serum superoxide dismutase and lysozyme activities. Also, no treatment effects were observed for whole-body protein, ash, and protein conversion efficiency. However, weight gain, feed efficiency, intraperitoneal fat, and whole-body lipid were significantly affected by the dietary treatments with CFP able to replace up to 40 to 58% of the SBM in the diet while providing similar fish performance and body composition as fish fed the control diet. Digesta samples from the posterior segment of the intestine were subjected to DNA extraction, followed by 16S rRNA gene (V3-V4 region) sequencing to profile the intestinal microbiota. A higher relative abundance of Aeromonas spp. was observed for fish fed the control diet. The remaining fish from the feeding trial were challenged with Edwardsiella ictaluri, and cumulative survival was monitored for 21 days. Survival after the bacterial challenge gradually increased as the inclusion levels of CFP increased in the diets, with the 100% replacement treatment being significantly different from the control diet. In conclusion, CFP is a promising alternative plant protein ingredient with high protein and phosphorus digestibility, and it can replace up to 40 to 58% of the SBM in feed formulations for juvenile channel catfish based on weight gain and feed efficiency while potentially increasing disease resistance against E. ictaluri.

Effects of yeast extract supplemented in diet on growth performance, digestibility, intestinal histology, and the antioxidant capacity of the juvenile turbot (Scophthalmus maximus).

An 8-week feeding experiment was conducted on the juvenile turbot (Scophthalmus maximus) to evaluate the influence of yeast extract (YE) supplementation in the diet on growth performance, feed utilization, body composition, nutrient digestibility, intestinal histology, and antioxidant capacity. Four experimental diets were formulated with graded levels of yeast extract 0 (YE0), 1% (YE1), 3% (YE3), and 5% (YE5) and fed to turbots (initial body weight: 4.2 ± 0.1g) with three replicates per diet and 200 fish in each replicate, respectively. The results showed that turbots fed with diets YE1 and YE3 displayed a significantly higher specific growth rate and protein efficiency rate than those fed with diets YE0 and YE5, while the feed conversion ratios in YE1 and YE3 groups were lower than those in YE0 and YE5. Fish fed with diets YE3 and YE5 showed higher body crude protein contents than those in groups YE0 and YE1. The highest apparent digestibility coefficients for dry matter and crude protein, digestive enzyme activities (trypsin, lipase, and amylase), and the height of the intestinal fold were observed in the YE3 group. YE3 treatment displayed a significantly higher superoxide dismutase (SOD) activity than the YE0 group, while the malondialdehyde (MDA) content in YE1 was significantly lower than those in YE0 and YE5. No significant difference was observed in serum physiological and biochemical parameters among all treatments. Overall, appropriate dietary supplementation of the yeast extract could improve the growth performance, digestibility, and antioxidant capacity of the juvenile turbot, and the recommended yeast extract level in the feed is 2.47%.

Evaluation of in vitro and in vivo digestibility of potential feed ingredients for juvenile Yellowtail Snapper

AbstractObjectiveThe carnivorous Yellowtail Snapper Ocyurus chrysurus has the potential for production in aquaculture. However, there is a lack of studies investigating the digestibility of ingredients needed to formulate balanced diets for this species.MethodsThe in vitro protein digestibility of fish meal (FM), poultry by‐product meal (PBM), poultry meal (PM), protiblend, canola meal (CM), soybean meal, and wheat gluten was evaluated using the pH‐stat technique. The in vivo digestibility was determined by formulating test diets with a 70:30 ratio of the reference diet and the test ingredients.ResultIn terms of in vitro digestibility, FM, PBM, and PM exhibited the highest degree of hydrolysis (DH). Conversely, PBM displayed the lowest apparent digestibility coefficient of protein (ADCprotein) in the in vivo digestibility test. Meanwhile, FM, PM, and CM demonstrated higher values of protein digestibility. Beta regression between ADCprotein and the DH and ash content of the ingredients resulted in a high correlation (R2 = 0.94).ConclusionThe results of the present study indicate that Yellowtail Snapper efficiently digested and absorbed FM, PM, and CM ingredients, which contain a lower content of ash.

Evaluation of andean lupin (Lupinus mutabilis) seed meal as a dietary component on growth performance, feed utilization, nutrient digestibility, and liver histology of rainbow trout (Oncorhynchus mykiss) Juveniles

This study aimed to investigate the effects of dietary inclusion of Andean lupin (Lupinus mutabilis) on the growth performance, carcass composition, liver histology, and nutrient digestibility in rainbow trout (Oncorhynchus mykiss) juveniles. The experiment involved triplicate groups of fish (initial body weight 32.10 ± 0.79 g) fed four extruded experimental diets with varying levels of Andean lupin (0, 50, 100, and 200 g kg−1) twice a day to apparent satiety over a period of 40 days. Faecal samples were collected daily for nutrient digestibility analysis. No significant correlations were observed between the dietary inclusion of Andean lupin and final weight, survival, weight gain, protein efficiency retention, thermal growth rate, feed conversion rate, and feed intake (P > 0.05). Similarly, there were no significant relationships between increasing dietary inclusion of Andean lupin and apparent digestibility coefficients for dry matter, crude protein, carbohydrate, and energy. However, the inclusion of Andean lupin led to a decrease in apparent digestibility coefficients for ash (R2 =0.6, P < 0.05). Furthermore, the digestibility of Mg and Zn decreased in a quadratic manner (P < 0.01) with increasing levels of Andean lupin inclusion. The dietary treatments did not significantly affect whole-body composition, spleen-somatic index, and intestine-somatic index (P > 0.05). However, the hepatosomatic index decreased quadratically with increasing inclusion of Andean lupin (R2 =0.51, P < 0.05), likely due to a slight reduction in cytoplasmic vacuolization of hepatocytes. In conclusion, this study demonstrates that Andean lupin is a promising plant protein ingredient for rainbow trout diets. It can be included at levels up to 200 g kg−1 without adversely affecting growth performance and nutrient digestibility. These findings contribute to the expanding knowledge on alternative protein sources in aquaculture feed formulation.

Establishment of hydrolysates from enzymatic plant and fish protein by-products into fish nutrition

The aim of this research was to scientifically prove the technology for producing plant-fish hydrolysates from sunflower meal and fish waste (carp processing) and to develop scientifically based recipes for protein hydrolysates and feed using it for carp of different ages. Compositions from fish waste and different amounts of sunflower meal have been developed, the chemical composition of the compositions and the digestibility of protein by carp have been studied. It was distinguished that the best characteristics when studing the nutritional value and digestibility of crude protein have the protein hydrolysates of fish waste and sunflower meal, taken in a ratio of 1 to 2. Accordingly, in this case, a high content of dry matter was noted 65.57 ± 0.18%), crude protein 41.92±0.72%, crude fat 2.74±0.12% and low crude fiber 14.34±0.10%, and the apparent protein digestibility coefficient was 78.8%. The compiled enzyme compositions for enzymatic hydrolysis are optimal at a temperature of 50°C and the proportion of the enzyme composition for fermentation in an amount of 5%, containing enzyme preparations: Protozyme - 40%, Cellulase - 35%, Lipase - 10% and Amylorizin - 15%.

Intestinal microbiota differences associated with physiological health, meat quality, and regulating mineral interactions of Penaeus vannamei fed organic manganese

The objective of this study was to investigate the effects of organic manganese (Mn) on the health status of white shrimp (Penaeus vannamei) and the potential correlations between intestinal microbiota and host health, meat quality, and mineral interactions. An 8-week experiment was designed with 7 dietary treatments: C0, no Mn supplementation; S20, 20 mg/kg Mn from MnSO4·H2O (inorganic); SO, 10 mg/kg inorganic Mn and 5 mg/kg Mn from Mn-proteinate (organic); O10, O20, O30 and O40, 10, 20, 30 and 40 mg/kg organic Mn, respectively. The 840 shrimp (approximately 5.30 g) were randomly allocated into 21 tanks, with each diet group containing 3 tanks and each tank accommodating 40 shrimp. The results showed that 10 mg/kg organic Mn supplementation is optimal to replace 20 mg/kg inorganic Mn. Compared with inorganic Mn, organic Mn shaped healthier intestinal microbiota communities and enhanced the competitive advantage of shrimp for Mn uptake, which resulted in promoting nutrition metabolism (higher apparent digestibility coefficient (ADC) of crude protein (P = 0.031) and concentrations of glucose (P = 0.013), triglyceride (P < 0.01) and total cholesterol (P < 0.001)), enhancing antioxidant capacity and immune response (P < 0.05), improving meat quality (P < 0.05), and regulating iron content in whole body and muscle, zinc content in muscle and ADC of copper and zinc (P < 0.01). Pearson's correlations were observed between gene expression analysis of the immune response and antioxidant capacity, Crude proteinADC, meat texture, and dietary organic Mn, between ADC of copper and zinc, muscle content of iron and zinc (r = 0.55, 0.79, 0.93, −0.91, −0.90, respectively, P < 0.001). In conclusion, organic Mn affects shrimp health status, meat quality and mineral interactions which correlate with changes of the intestinal microbiota.

Nutritional value of torula yeast as an alternative protein feedstuff for hybrid Striped Bass (White Bass × Striped Bass)

AbstractObjectiveTwo separate trials were conducted to evaluate the digestibility of a novel alternative ingredient, enhanced torula yeast (TY) Cyberlindnera jadinii, in diets for hybrid Striped Bass (HSB; White Bass Morone chrysops × Striped Bass M. saxatilis) and to evaluate graded inclusion levels of this product when replacing soybean products.MethodsIn trial 1, the digestibility of TY was determined by testing a reference diet and a TY diet (reference and TY ingredient at an 80:20 ratio). A total of 90 fish were fed the experimental digestibility diets for 21 days, and fecal samples were collected using the stripping technique. In trial 2, a comparative feeding trial evaluated the replacement of soybean meal by TY on a crude protein basis at 50, 100, 200, and 300 g of TY/kg of experimental diet. A total of 150 HSB (18.6 ± 0.21 g/fish [mean + SE]) were distributed among fifteen 110‐L glass aquaria. Each diet was fed to triplicate groups of fish for 9 weeks.ResultIn trial 1, apparent digestibility coefficients for protein, lipid, organic matter, and energy of TY were 0.97, 0.98, 0.75, and 0.75, respectively. The availability of essential amino acids also was generally high, ranging from 0.74 to 0.99. For trial 2, a second‐order polynomial regression indicated that the optimal inclusion levels of TY in diets were 102, 112, and 109 g/kg for weight gain, feed efficiency, and protein conversion efficiency, respectively. However, the muscle yield linearly decreased with the graded inclusion levels of TY. Linear increases in intraperitoneal fat, hepatosomatic index, and whole‐body lipid were observed as the inclusion of TY increased in the diet.ConclusionIn conclusion, nutrients from TY were well utilized by HSB, and it can replace soybean products without affecting growth performance, with the optimal TY inclusion level being 102–112 g/kg of diet.

Nutrient Digestibility and Retention of Potential Feed Ingredients for Rainbow Trout (Oncorhynchus mykiss W.) Aquaculture in Iran

To overcome the aquafeed challenges for aquaculture in Iran, the world’s largest rainbow trout producer, the nutrient digestibility and retention of eight rendered poultry by-products, and two plant protein sources were investigated. The test ingredients were added to a casein-based semipurified reference diet as control diet and fed to juvenile rainbow trout in three runs. During the experimental runs, test ingredients were added to the control diet in a ratio of 30 : 70. The diets were then fed to the animals in four replicates. TiO2 was used as marker and feces were collected by settling method. The apparent protein digestibility coefficient for poultry by-product meals (PBM), feather meals (FeM), poultry protein concentrate (PPCon), blood meal (BM), canola meal (CM), and Iranian soybean meal (IRSBM) were 73%–93%, 73%–96%, 100%, 87%, 94%, and 97%, respectively. The nitrogen productive value for PBM ranged 27%–46%, both PPCon and IRSBM 37%, CM 24%, BM 23%, and FeM from −6% to 18%. Citric acid supplementation of the alkaline thermochemically hydrolyzed FeM improved the digestibility of crude lipid and organic matter from 6% and 88% to 55% and 92%, respectively. The assessment of digestibility as well as nutrient retention analysis for tested feed components indicated that refined PBM and PPCon, both CM and IRSBM could be used in rainbow trout diets as value-added and eco-friendly protein sources. The findings of this study can assist fish nutritionists and key players in the aquafeed industry in adopting a sustainable approach to aquaculture by selecting locally available raw materials that demonstrate high nutrient retention in rainbow trout.

Organic Ingredients as Alternative Protein Sources in the Diet of Juvenile Organic Seabass (Dicentrarchus labrax).

The use of organic ingredients as a source of protein in aquaculture diets has gained significant attention due to the growing demand for organic seafood products. This study aimed to evaluate the potential for the use of organic ingredients as protein sources in the diet of juvenile organic seabass (Dicentrarchus labrax). A total of 486 juvenile seabass with an average weight of 90 g were fed six diets containing varied organic proteins. The control group (CON) was fed a diet with conventional fishmeal from sustainable fisheries as the primary protein source. The other five groups were fed diets with different compositions: organic Iberian pig meal byproduct (IB diet), a combination of organic Iberian pig meal byproduct and insect meal (IB-IN diet), a mix of organic Iberian pig meal byproduct and organic rainbow trout meal byproduct (IB-TR diet), a blend of organic rainbow trout meal byproduct and insect meal (TR-IN), and a mixed diet containing all of these protein sources (MIX diet). Over a 125-day feeding trial, growth performance, feed utilisation, feed digestibility, and histological parameters were assessed. The results showed that the fish fed the control diet had the highest final weight and specific growth rate, followed by the fish fed the TR-IN and IB-TR diets. The IB-TR diet had the highest apparent digestibility coefficients (ADCs) for protein, while the TR-IN diet had the lowest. Histological analysis revealed that fish fed the control diet had the largest nucleus diameter and hepatocyte diameter. Use of IN seems to penalise performance in several ways. Fish fed diets containing insect meal grew less, and those diets had lower digestibility. Fish fed the TR and IB diets grew at rates near that of the control, and the feed had acceptable digestibility.

Extruded diet macronutrient digestibility: plant-based (vegan) vs. animal-based diets in client-owned healthy adult dogs and the impact of guardian compliance during in-home trials

IntroductionPlant-based (vegan) diets for dogs are commercially available, however, research investigating long-term nutritional adequacy of these diets is scarce. Use of client-owned animals has become increasingly popular for apparent total-tract nutrient digestibility (ATTD) studies, yet low guardian compliance with the study protocol, such as providing daily dietary intake information, is a challenge. However, the impact of low diet reporting compliance on the overall ATTD results is unknown.MethodsSixty-one, client-owned healthy adult dogs completed a randomized, double-blinded longitudinal study. Dogs were randomly assigned into two groups that were fed either a commercial extruded meat-based diet (MEAT, n=30) or an experimental extruded vegan diet (PLANT, n=31) for 12 weeks. At the end of the study, pet guardians performed a 72-hour total fecal collection for ATTD assessment. Pet guardians were asked to complete a food diary for the duration of the trial, however only a subset of guardians (n=35) provided this food diary at the end of the study.ResultsNo evidence of an association between pet guardians providing a food diary and apparent digestibility coefficients (ADC) of crude protein (CP) (p=0.14), crude fat (EE) (p=0.72), and dry matter (DM) (p=0.68) was found. Apparent digestibility coefficients for CP (p=0.52), EE (p=0.78), and DM (p=0.43) did not differ between PLANT and MEAT. Body weight and age were found to be associated with CP (p=0.03) and DM (p=0.01) digestibility, but no association with EE (p=0.07) digestibility was present.DiscussionThese results indicate that vegan- and animal-based diets with similar nutrient profiles can have comparable nutrient digestibility. Moreover, presence or absence of a guardian-reported food diary had no effect on the overall results of the ATTD study. Further studies investigating guardian compliance for ATTD trials are needed to develop a standardized protocol and reduce current challenges and limitations related to pet guardian’s participation in digestibility trials.

Assessment of hydrolysis of partially defatted black soldier fly larvae meal in diets for Nile tilapia Oreochromis niloticus

The chitin content of black soldier fly (Hermetia illucens) larvae meal (BSFM) is known to negatively affect its digestibility by fish. Nile tilapia (Oreochromis niloticus) tolerates well BSFM in the diet. However, chemical hydrolysis of dietary BSFM has not previously been attempted for this species. In this study, based upon a low-fishmeal control diet (40% crude protein and 9% crude fat), three levels of dietary protein, 25%, 50%, and 75%, were replaced by partially defatted BSFM, subjected or not to a prior hydrolysis treatment with formic acid and fed to Nile tilapia juveniles (initial body weight: 0.26 ± 0.00 g). The hydrolysis treatment did not modify greatly the proximate and amino acid composition of the diets, nor did it improve their in vivo apparent digestibility coefficients of dry matter or crude protein. However, it significantly increased the contents of arginine, taurine, and tyrosine, and significantly reduced the contents of methionine, valine, aspartic acid, and glutamic acid in muscle tissue of Nile tilapia. The hydrolysis treatment also decreased fish growth significantly. In contrast, for diets not containing hydrolyzed BSFM, not only did fish fed all three levels of protein replacement grow satisfactorily, but the diets with the levels of replacement of 50% and 75%, with final weights of 23.04 and 23.11 g, respectively, elicited superior fish performance, as compared to the diet with 25% replacement (final weight of 20.09 g). In addition, all three protein replacement diets produced significantly greater growth than the control diet (final weight of 17.72 g). The actual levels of inclusion of BSFM were, respectively, 14.11%, 28.21% and 42.33% of diet, the latter being the highest inclusion level of BSFM reported to date for successful growth of Nile Tilapia.

Effects of dietary-reduced nitrogen (N) and phosphorus (P) on N and P balance, retention and nutrient digestibility of contemporary fattening pigs fed ad libitum

ABSTRACT The reduction of nitrogen (N) and phosphorus (P) in fattening pigs’ diets is one possible approach to lower N and P excretion in livestock farming relative to N and P intake. Due to the implementation of the European Nitrates Directive and the consecutive amendments to the German fertiliser legislation since 2017, N- and P-reduced diets for fattening pigs are becoming more and more important and are increasingly used in practice. To investigate the effects of such diets on N and P balance and retention as well as on nutrient digestibility of contemporary fattening pigs, a balance experiment was performed with eight barrows (average live weight = 61.5 ± 2.1 kg) which were surgically fitted with a simple T-cannula at the terminal ileum. The pigs received a control diet meeting nutrient requirements (CON) and an N- and P-reduced diet (NPred) ad libitum (n = 4/diet) in a 3-phased feeding regimen (3 weeks/phase). In the last week of each phase, faeces and urine were collected quantitatively for 5 days followed by a 2 × 12 hours collection of ileal digesta. Daily feed intake, live weight gain and feed-to-gain ratio did not differ between CON and NPred. NPred-fed pigs consumed 10.5% (p = 0.006) and excreted 28.3% (p = 0.028) less N than CON-fed pigs. Phosphorus excretion was lowered by 15.1% in NPred-fed pigs (p = 0.012). N and P retention did not differ between CON and NPred, but were elevated in comparison to other studies. N and P efficiency, expressed as nutrient retention divided by nutrient intake, was higher in NPred – than CON-fed pigs (N: 68 vs 60%, P: 54.2 vs 49.3%). Apparent post-ileal digestibility coefficient (DCpost-ileal) and apparent total tract digestibility coefficient (DCtotal) of crude protein were higher in NPred – than CON-fed pigs (p < 0.013), but apparent precaecal digestibility coefficient (DCpc) of crude protein was unaffected by diet. DCpc, DCpost-ileal and DCtotal of P were similar for CON- and NPred-fed pigs. NPred-fed pigs showed an elevated DCpc and DCtotal of organic matter, N-free-extractives and starch compared to CON-fed pigs. DCpc of calcium was also higher in NPred-fed pigs. In conclusion, the results suggest that N- and P-reduced feeding of fattening pigs remains an effective strategy to lower the N and P release into the environment. Furthermore, results indicate that N- and P-reduced feeding leads to a higher N and P efficiency in contemporary fattening pigs.

Dietary citric acid improves phosphorus and calcium availability and intestinal morphology of Nile tilapia Oreochromis niloticus

Citric acid is an organic acid, which has been used as a feed additive because it has a reasonable cost, pleasant taste, and fast assimilation, showing positive effects on the growth and health of some livestock and aquatic species. This study aimed to evaluate the effects of increased levels of citric acid (0, 10, 20, 30, and 40 g/kg) in an isonitrogenous (280.00 g/kg of digestible protein) and isoenergetic diet (12.98 MJ/kg of digestible energy) on growth performance, body composition, apparent digestibility of nutrients and minerals, hematology, pH in stomach and intestine, and intestinal histomorphometry of Nile tilapia juveniles. Fish (n = 200, initial average weight of 14.59 ± 0.81 g) were randomly distributed in 25 experimental tanks (five replicates per treatment) and fed experimental diets over a 40-day period. Increasing levels of citric acid supplementation resulted in a decrease in the pH of the experimental diets (P = 0.021). However, no significant differences in pH levels were observed in the stomach and intestine among the treatments (P > 0.05). Citric acid supplementation did not significantly (P > 0.05) affect the growth performance variables, body composition, or the apparent digestibility coefficients (ADC) of dry matter, crude protein, gross energy, ether extract, and ash of the diets. Fish fed diets with 10 and 30 g/kg citric acid exhibited higher values for total leukocytes (P = 0.043) and total plasma protein (P = 0.019) compared to the control group. Diets supplemented with 20 g/kg citric acid showed a higher ADC value for phosphorus (P = 0.027) and calcium (P = 0.032) compared to the control. Additionally, fish fed with diets containing 20 g/kg citric acid demonstrated higher values for villus height (P = 0.002) and width (P = 0.048), crypt depth (P = 0.035), and villus: crypt ratio (P = 0.014) compared to the control group. In conclusion, the supplementation of 20 g/kg citric acid improved the availability of phosphorus and calcium and positively influenced the intestinal morphology of Nile tilapia juveniles.

Effect of replacing fish meal with chicken gut meal on growth, immune parameters, and metabolism of juvenile Fat Greenling Hexagrammos otakii

AbstractObjectiveChicken gut meal (CGM) is reasonably priced and rich in nutrients and can become a new source of protein in the diets of major aquatic products, such as fish and shrimp.MethodsAn 8‐week feeding trial was conducted to comprehensively investigate the beneficial effects of CGM on juvenile Fat Greenling Hexagrammos otakii. Juveniles (1.58 ± 0.06 g [mean ± SE]) were fed with different levels of CGM in replacement of fish meal (FM) in the basal diet: 0% (CGM0), 25% (CGM25), 50% (CGM50), 75% (CGM75), and 100% (CGM100) replacement, representing a dietary CGM level of up to 40 g/kg.ResultThe results showed that the percent weight gain; specific growth rate; feeding rate; feed conversion ratio; hepatosomatic index; and apparent digestibility coefficients of dry matter, protein, and lipid were significantly improved among the experimental groups. Moreover, the activities of superoxide dismutase and catalase were significantly increased in the CGM25 and CGM50 groups, respectively. The activities of acid phosphatase and alkaline phosphatase were significantly decreased in the CGM75 and CGM100 groups. Triglycerides and total cholesterol were significantly increased in the CGM50 and CGM75 groups, respectively. Fish in the CGM100 and CGM75 groups had significantly higher activities of aspartate aminotransferase and alanine aminotransferase than the control. Moreover, the relative expression levels of the fatty acid synthase and acetyl‐coenzyme A carboxylase alpha genes were significantly increased in the CGM75 and CGM100 groups, while the gene expression levels of hormone‐sensitive lipase and peroxisome proliferator‐activated receptor alpha were significantly decreased.ConclusionIn summary, the optimal replacement level of FM with CGM was shown by curve equation analysis to be 61.30%, and their dosages were 24.52 and 15.48 g/kg, respectively.

Solid-State Fermentation as Green Technology to Improve the Use of Plant Feedstuffs as Ingredients in Diets for European Sea Bass (Dicentrarchus labrax) Juveniles.

This study aimed to evaluate the utilization by juvenile European sea bass of a SSFed PF mixture with Aspergillus niger CECT 2088. A 22-day digestibility and a 50-day growth trial were performed testing four diets, including 20 or 40% of an unfermented or SSFed PF mixture (rapeseed, soybean, rice bran, and sunflower seed meals, 25% each). SSF of the PF added cellulase and β-glucosidase activity to the diets. Mycotoxin contamination was not detected in any of the experimental diets except for residual levels of zearalenone and deoxynivalenol (100 and 600 times lower than that established by the European Commission Recommendation-2006/576/EC). In diets including 20% PF, SSF did not affect growth but increased apparent digestibility coefficients of protein and energy, feed efficiency, and protein efficiency ratio. On the contrary, in diets including 40% PF, SSF decreased growth performance, feed intake, feed and protein efficiency, and diet digestibility. SSF decreased the intestinal amylase activity in the 40% SSFed diet, while total alkaline proteases decreased in the 20% and 40% SSFed diets. Hepatic amino acid catabolic enzyme activity was not modulated by SSF, and plasma total protein, cholesterol, and triglyceride levels were similar among dietary treatments. In conclusion, dietary inclusion of moderate levels of the SSFed PF, up to 20%, improves the overall feed utilization efficiency without negatively impacting European sea bass growth performance. The replacement of PF with the SSFed PF mixture may contribute to reducing the environmental footprint of aquaculture production.