Digestibility Coefficients Of Crude 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.

Influence of Jerusalem artichoke tuber as a prebiotic on the nutrient utilization, weaning stress indicators and immunocompetence of crossbred calves during the pre- and post-weaning phases

This study explored the potential prebiotic properties of pulverized Jerusalem artichoke tuber (JAP) in pre- and post-weaned calves. Accordingly, 24 fifteen-day-old calves were randomly assigned to four groups (n = 6). The groups received JAP supplementation at levels of 0 (CON), 1 (JAP1), 2 (JAP2), and 3 (JAP3) percent of dry matter intake (DMI) during the first 60 days of the 120-day experiment. Two 6-days digestion trials were conducted: one during the 4th week of the experiment (pre-wean), and the second during the tenth week (post-wean). Additionally, serum concentrations of cortisol and epinephrine were measured in both the pre- and post-weaning phases to assess the stress levels. Immunocompetence of the calves during both the stages was evaluated through lymphocyte proliferation response. In the pre-weaning phase, the calves supplemented with JAP had better (P < 0.05) protein intake and digestion compared to the control group. In the post-weaning phase, the JAP supplemented groups exhibited significantly (P < 0.05) improved digestibility coefficients for dry matter, organic matter, crude protein, ether extract, and neutral detergent fibre. Although cortisol levels didn't show significant differences (P > 0.05) between the groups during both pre-weaning and post-weaning stages, the post-weaning stage did reveal a significant reduction (P < 0.05) in epinephrine levels in JAP1 compared to the other groups. Additionally, JAP supplementation enhanced (P < 0.05) the calves' response to lymphocyte proliferation during the post-weaning phase. Considering the improved nutrient digestibility, enhanced systemic immunity, and reduced epinephrine levels observed in the JAP supplemented groups, our findings suggest that JAP may have promising potential as a prebiotic for calves.

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.

Paecilomyces variotii (PEKILO®) in novel feeds for Atlantic salmon: Effects on pellet quality, growth performance, gut health, and nutrient digestibility and utilization

Filamentous fungi have potential as an alternative protein source for use in aquafeeds due to their high protein content and bioactive components. Paecilomyces variotii (PEKILO® mycoprotein) is a β-glucan- and nucleotide-rich filamentous fungi with a crude protein (CP) content of 60–70%. A 9-week feeding trial was conducted to evaluate the effects of P. variotii in diets for Atlantic salmon (initial average body weight of 24 g fish−1) reared in freshwater. Four experimental diets were formulated. Diet 1 was a control diet based on fish meal, soy protein concentrate, and wheat gluten meal. Diets 2, 3, and 4 were formulated so that P. variotii replaced 5, 10, and 20% of the CP content of the diets, respectively. Results showed that dietary inclusion of P. variotii was associated with changes in physical pellet quality, including significant linear (p < 0.0001) and/or quadratic (p < 0.01) decreases in pellet length, width, expansion, and durability. Conversely, significant linear (p < 0.0001) and quadratic (p < 0.025) increases in water activity, bulk density, and water stability index were associated with increasing replacement of the CP content of the diets with P. variotii. There were no significant differences in weight gain, growth rate or feed intake among fish fed the experimental diets (p > 0.05), but a significant linear improvement (p < 0.025) in feed conversion ratio (FCR) with increasing dietary inclusion of P. variotii was observed. The apparent digestibility coefficients for CP and gross energy of the experimental diets decreased linearly (p < 0.01) with increasing dietary levels of P. variotii. Similar results were observed for the essential and non-essential amino acids. Despite reduced digestibility, linear increases in nitrogen (p < 0.01), energy (p < 0.025), and mineral (p < 0.001) retention efficiencies were associated with increasing dietary levels of P. variotii. In the distal intestine, dietary inclusion of P. variotii resulted in significant (p < 0.05) upregulation of several cytokines (ifng, il10, and tgfb), effector molecules (inos, arg1, sod), and transcription factors (irf4), suggesting both activation and control of the inflammatory response in this key mucosa-associated lymphoid tissue. Overall, replacement of 20% of the CP content of the diet with P. variotii reduced digestibility of the experimental diets, but did not affect growth performance and improved FCR and nutrient utilization efficiency of salmon. Thus, P. variotii is a promising ingredient with potential for use in salmonid aquafeeds to improve fish performance and health.

Effect of Dietary Seaweed Supplementation on Growth, Feed Utilization, Digestibility Co-efficient, Digestive Enzyme Activity and Challenge Study against Aeromonas hydrophila of Nile Tilapia Oreochromis niloticus

Background: The present study aimed to determine the growth, digestibility co-efficient, digestive enzyme activity and disease resistance of juvenile GIFT tilapia fed with Ulva seaweed meal supplemented diet. Methods: The study was undertaken with different inclusion levels of Ulva seaweed meal (USM) such as raw (UR) and fermented (UF) Ulva meal (UR-5, UR-10, UR-15, UF-5, UF-10 and UF-15% of diet) and control feed (C) for a period of 60 days. Result: GIFT fed with fermented Ulva meal at a 10% inclusion level in their diet exhibited the highest growth performance (41.43 g) followed by UF5 (41.07±0.43 g), UR5 (39.65±0.36 g), control (39.09±0.20 g), UF15 (38.67±0.26 g), UR10 (38.47±1.47 g) and UR15 (35.77±0.35 g) diet. The Highest Apparent Digestibility Coefficient (ADC) for Crude Protein (85.14±0.91%) was observed in fishes fed with fermented Ulva meal at a 10% inclusion rate than other treatments and the control groups for Dry Matter, Ether Extract, and Gross Energy. The enzymatic activities of digestive enzymes, namely Amylase activity (0.029±0.00 units/mg protein/min), Protease activity (0.147±0.0 units/mgprotein/min) and Lipase activity (0.273±0.05 units/mg protein/min), showed higher levels in the group of fishes fed with a diet containing 10% fermented Ulva meal, as compared to the other treatment groups and the control. Increased survival rate (86.66%) was observed when the fishes were challenged with Aeromonas hydrophila at the end of the trial for Ulva based diets. The results obtained on histopathology showed the presence of lower degree levels of infection in 10% fermented Ulva meal supplementation.The present study concluded that dietary Ulva meal requirement for juvenile GIFT tilapia can be at 10% of Ulva Fermented (UF) and UF-5, Ulva Raw (UR) 5%, control (C), UF-15, UR-10 and UR-15 diet respectively.

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 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.

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.

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.

Spirulina in diets of Japanese quail: Productive performance, digestibility, and egg quality

The present study evaluated the effects of dietary inclusion of spirulina on productive performance, nutrient utilization, and egg quality of Japanese quails. One hundred twenty quails were included in a completely randomized design with four treatments and five replicates. Treatments consisted of a control diet and three diets containing 0.3, 0.6, or 0.9% of spirulina powder. Spirulina inclusion had no effect (p &gt; 0.05) on the productive performance, digestibility coefficients of dry matter and ether extract, calcium and phosphorus retention, weight and pH of the eggs, yolk index, albumen quality, and eggshell thickness when compared with the control diet. However, crude protein consumption was higher (p &lt; 0.05) and the digestibility coefficient of crude protein was lower (p &lt; 0.05) in birds in the 0.9% and 0.3% spirulina inclusion groups, respectively. The weights of the yolk and eggshell were improved (p &lt; 0.007) by the inclusion of 0.6% and 0.9% and 0.9% spirulina, respectively. Quails fed diets containing 0.3% and 0.6% spirulina exhibited lower specific gravity of eggs (p &lt; 0.019) than those fed diets containing 0.9% spirulina. Therefore, spirulina inclusion at 0.9% improved the eggshell quality and reduced the total lipid levels in the yolks.

Impact of β-glucan dietary supplementation on productive, reproductive performance and physiological response of laying hens under heat stress conditions

The exploration for effective in-feed additives is growing owing to the global climatic change trend to alleviate the negative effects of heat stress in laying hens. This research assessed the potential of using B-glucan (G) as an antiheat stress agent in Matrouh laying hens subjected to early heat shock programs during the growing period. Factorial design (3 × 3) was used, including 3 levels of heat stress (control, heat shock at 3 d and at 3 d and 8 wk of age) and 3 levels of β-glucan (0, 100, and 200 mg β-glucan /kg diet). During the first 12 wk of egg production (EP), treatments were exposed to heat challenge. The results revealed that heat shock program applications at 3 d and 8 wk of age significantly decreased body weight at 36 wk of age (P < 0.05) and reduced (P < 0.05) feed intake (FI). While significantly (P < 0.05) improved feed conversion ratio (FCR), hemoglobin, RBCs, WBCs, immunoglobulin M (IgM), immunoglobulin G (IgG), and Heat shock protein (HSP70) of the Liver (P < 0.01) as compared with the control group. At the same time, there was a decrease in lymphocyte%, H/L ratio, cortisol, and T3 compared to the thermo-neutral control. When compared to the control group, hens fed a diet containing 200 mg of βG significantly (P < 0.05) improved body weight at 16 wk and final weight at 36 wk, feed conversion (FCR) (g. feed/g. egg mass), hen-day egg production, and egg mass, as well as the digestibility coefficients of crude protein (CP), dry matter (DM), metabolizable energy (ME), and cortisol. The interactions between heat chock programs and βG levels were nonsignificant for the most studied traits except daily feed intake. Therefore, the early heat shock exposure 2 times and supplementation of Β-glucan (βG) at 200 mg/kg diet during the growth period for laying hens that are exposed to heat stress during the reproductive period could improve productive, reproductive performance, HSP70 level and enhance immunity responses.

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 dietary supplementation of inulin with low and high concentrate diet on growth performance and nutrient digestibility in Barbari goats

This study aimed to determine the effect of dietary supplementation of inulin on growth performance, feed conversion and nutrient digestibility in Barbari goats fed high and low concentrate diet for a period of 90 days. Twenty four yearling female Barbari goats were randomly divided into four equal groups (n=6) according to average body weight (18.24±1.16 kg). Treated animals in Group 1 were fed low concentrate diet (LCD; concentrate roughage ratio 40:60) and Group 2 (LCIN) with 2% inulin supplementation (% DM basis). Similarly, Group 3 was fed high concentrate diet (HCD; concentrate roughage ratio 60:40) and Group 4 (HCIN) with 2% inulinsupplementation. Results showed that average daily gain (ADG) and feed conversion efficiency (FCE) were higher in inulin supplemented groups than the non-supplemented group. There was no increase in mean live body weight (BW) and dry matter intake (DMI) with inulin supplementation either in LCD or HCD treatment groups.The mean body condition score (BCS) was also similar in all groups. However, faecal score (FS) was superior in inulin supplemented group observed after 30 days of feeding trial. There was significant improvement in the digestibility coefficient of crude protein and DCP intake. It was concluded that inulin supplementation either in high concentrate and low concentrate diet of growing goats resulted in improvement in growth performance, faecal score and nutrient digestibility.

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.