Effects of dietary protein levels and protease supplementation on growth performance, carcass traits, meat quality, and standardized ileal digestibility of amino acid in Pekin ducks fed a complex diet

Reducing the dietary starch:protein ratios in low-protein diets enhanced the growth performance of goslings from 1 to 28 days of age

The current study aimed to explore the suitable starch: protein ratios under different dietary protein levels for goslings. A total of 360 male 1-day-old Jiangnan White goslings were randomly divided into 6 groups with six replicates containing ten goslings each. The experimental design consisted of a 3 × 2 factorial array of treatments. Three protein levels (18%, 16%, 14%) and two starch: protein ratio (S: P ratio) types (standard, reduced) were formulated. The results showed that: reducing the S: P ratio at the same dietary protein level increased weight gain (WG), average daily gain (ADG), and average daily feed intake (ADFI) of goslings (P < 0.05). Lowering the protein level increased feed-to- gain ratio (F/G) at the same dietary S: P ratio type. Both decreasing dietary protein levels and reducing S: P resulted in an increase (P < 0.05) in the serum albumin (ALB) content of goslings. Protein at 18% level, minimized serum total cholesterol (TC) in goslings. Reducing the dietary S: P ratio elevated serum lipid concentration. In reduced S: P ratio diets, serum Leucine (Leu) decreased and Threonine (Thr) concentration increased. The reduction in dietary protein level and S: P ratio significantly affected the amino acid composition of muscles. The varied levels of protein and S: P ratio types interacted to influence the starch digestibility of distal jejunum. In addition, the reduced S: P ratio attenuates α-amylase activity of jejunal chyme. Moreover, SGLT1 and GLUT2 genes expression were generally down-regulated, and SLC7A5 gene expression was up-regulated in reduced S: P ratio groups. In summary, the diet with 14% protein level, and 2.97 starch: protein ratio is recommended to use in gosling's growth phase of 1 to 28 days.

Effects of genotype and sex on carcass composition, meat quality, digestive tract morphometries and leg bone dimensions of spent parent Pekin ducks

The purpose of the present study was to analyze carcass composition, physicochemical properties, muscle texture, and structure, as well as morphometry of the digestive tract and leg bone dimensions of Cherry Valley ducks (SM3 Heavy hybrid) and Orvia ducks (ST5 Heavy hybrid) after laying. A total of 32 ducks were dissected, 8 females and 8 males from each breeding set. Analysis of meat quality (breast muscle, leg muscle) in terms of color (L*, a*, b*), acidity (pH24), electrical conductivity (EC24), and basic chemical composition (protein, water, fat, collagen) was performed. Analysis of the texture and structure of the pectoral muscle was also performed. The dimensions of the various lengths of the digestive tract and the dimensions of the tibia and femur were analyzed. Cherry Valley ducks after laying have better slaughter performance and a higher proportion of breast muscle in the carcass (P < 0.001). Also more favorable chemical composition (protein, fat, water) and physical properties (acidity, electrical conductivity, thermal loss) of muscle. In terms of texture characteristics, the pectoral muscle of Cherry Valley ducks was more elastic and cohesive, but also more flexible with higher viscosity, while the pectoral muscles of Orvia ducks in terms of structure were characterized by smaller values of the analyzed characteristics (cross-sectional area of fibers and smaller vertical and horizontal diameter). Analyzing the morphometry of the digestive system, Orvia ducks were characterized by longer sections of the digestive tract, which certainly has a beneficial effect on the absorption of nutrients. In terms of tibia and femur measurements taken, there were no differences between genotypes, while males were characterized by higher values of the analyzed traits compared to females.

Effect of Dietary Crude Protein Reduction Levels on Performance, Nutrient Digestibility, Nitrogen Utilization, Blood Parameters, Meat Quality, and Welfare Index of Broilers in Welfare-Friendly Environments

We investigated the effects of feeding different levels of crude protein (CP) on broiler performance, blood characteristics, meat quality, nutrient and nitrogen (N) availability, stress levels, and welfare indicators in a welfare environment. A total of 625 eight-day-old male broilers were assigned to five dietary CP levels (control (CON) and 1-4% CP reductions) during the grower (8-21 days) and finisher (22-35 days) periods. The CON diet contained 20% CP in the grower phase and 19% in the finisher phase, while all birds received a 22% CP diet during the starter period (1-7 days). Intriguingly, reducing CP levels in the diet did not significantly affect growth performance. These results may be due to the adequate supplementation of essential amino acids in the diets of all treatments and the compensatory growth observed in the finisher phase. Low-CP diets reduced CP digestibility, N intake, and N excretion, while N retention efficiency improved (p < 0.001). Serum total protein (TP) levels decreased equally with decreasing CP in the diet, and the crude fat content in meat increased linearly (p < 0.01). The litter moisture content and pH decreased with lower CP levels, and the welfare indices (footpad dermatitis (FPD), serum corticosterone, etc.) improved (p < 0.01). In conclusion, an appropriate reduction in CP levels in their diet can enhance broiler welfare by reducing N excretion and improving litter quality without adversely affecting performance.

The effect of addition of calcium mineral in feed containing fishery wastes on egg production and hatching performance of Mojosari ducks

Calcium (Ca) is an essential mineral for eggshell formation and muscle contraction, and a lack of it can result in poor egg quality and decreased egg output in laying ducks. This study aims to see how feeding the mineral Ca in a ration containing Shrimp head meal and Bilis fish head affects the laying performance and quality of hatching eggs in Mojosari ducks. A total of 105 female and 15 male Mojosari ducks, aged 78 weeks, were raised for three months and randomly divided into 15 flocks (each flock containing seven females and one male duck). There were three kinds of treatment, namely P0 (control, without mineral), P1 (ratio of Shrimp head meal and Bilis fish head 2:1 + 1% mineral), and P2 ((ratio of Shrimp head meal and Bilis fish head 1:2 + 1% mineral). The findings revealed that adding mineral Ca to feed, including Shrimp head meal and Bilis fish head, had no significant influence (P>0.05) on laying Mojosari duck performance in terms of feed intake, egg production, egg weight, egg quality, ducklings produced, and income over feed cost (IOFC). Furthermore, Ca addition in the ration did not result in substantial increases (P>0.05) in fertility, hatchability, or egg size characteristics. Based on the findings of this study, feeding ducks with shrimp head meal and Bilis fish head can be used as an alternate calcium-free feed formulation.

Threonine Deficiency Increases Triglyceride Deposition in Primary Duck Hepatocytes by Reducing STAT3 Phosphorylation

Liver lipid metabolism disruption significantly contributes to excessive fat buildup in waterfowl. Research suggests that the supplementation of Threonine (Thr) in the diet can improve liver lipid metabolism disorder, while Thr deficiency can lead to such metabolic disorders in the liver. The mechanisms through which Thr regulates lipid metabolism remain unclear. STAT3 (signal transducer and activator of transcription 3), a crucial transcription factor in the JAK-STAT (Janus kinase-signal transducer and activator of transcription) pathway, participates in various biological processes, including lipid and energy metabolism. This research investigates the potential involvement of STAT3 in the increased lipid storage seen in primary duck hepatocytes as a result of a lack of Thr. Using small interfering RNA and Stattic, a specific STAT3 phosphorylation inhibitor, we explored the impact of STAT3 expression patterns on Thr-regulated lipid synthesis metabolism in hepatocytes. Through transcriptome sequencing, we uncovered pathways related to lipid synthesis and metabolism jointly regulated by Thr and STAT3. The results showed that Thr deficiency increases lipid deposition in primary duck hepatocytes (p < 0.01). The decrease in protein and phosphorylation levels of STAT3 directly caused this deposition (p < 0.01). Transcriptomic analysis revealed that Thr deficiency and STAT3 knockdown jointly altered the mRNA expression levels of pathways related to long-chain fatty acid synthesis and energy metabolism (p < 0.05). Thr deficiency, through mediating STAT3 inactivation, upregulated ELOVL7, PPARG, MMP1, MMP13, and TIMP4 mRNA levels, and downregulated PTGS2 mRNA levels (p < 0.01). In summary, these results suggest that Thr deficiency promotes lipid synthesis, reduces lipid breakdown, and leads to lipid metabolism disorders and triglyceride deposition by downregulating STAT3 activity in primary duck hepatocytes.

Black soldier fly larvae meal supplementation in a low protein diet reduced performance, but improved nitrogen efficiency and intestinal morphology of duck

OBJECTIVE

Reduced crude protein (CP) diets offer potential benefits such as optimized feed efficiency, reduced expenses, and lower environmental impact. The objective of this study was to evaluate black soldier fly larvae (BSFL) meal on a low-protein diet for duck performance, blood biochemical, intestinal morphology, gastrointestinal development, and litter.

METHODS

The experiment was conducted for 42 days. A total of 210-day-old male hybrid ducklings (5 replicate pens, 7 ducks per pen) were randomly assigned to 6 dietary treatments (3×2 factorial arrangements) in randomized design. The factors were CP level (18%, 16%, 14%) and protein source feed soybean meals (SBM), black soldier fly larvae meals (BSFLM).

RESULTS

Reduced dietary CP levels significantly decreased growth performance, feed intake, the percentage of nitrogen, pH (p<0.05), and tended to suppress ammonia in litter (p = 0.088); increased lipid concentration; and enhanced relative weight of gastrointestinal tracts (p<0.05). In addition, dietary BSFL as a source of protein feed significantly increased lipid concentration and impacted lowering villus height and crypt depth on jejunum (p<0.05).

CONCLUSION

In conclusion, the use of BSFLM in a low-protein diet was found to have a detrimental effect on growth performance. However, the reduction of 2% CP levels in SBM did not have a significant impact on growth performance but decreased nitrogen and ammonia concentrations.

Effects of protease enzyme supplementation and varying levels of amino acid inclusion on productive performance, egg quality, and amino acid digestibility in laying hens from 30 to 50 weeks of age

An experiment was conducted to evaluate the effects of protease supplementation and reduced digestible amino acid (dAA)/ crude protein (CP) level on productive performance, AA digestibility, and egg quality parameters in Hy-Line W-36 laying hen from 30 to 50 wk of age. A total of 768 hens (12 replicates of 8 hens per treatment) were equally and randomly allocated into 8 experimental diets in a 4 × 2 factorial arrangement of dAA/CP level (100, 95, 90, and 85% of breeder recommendation) and protease (exclusion or inclusion). Protease was added at 60 g/metric ton of feed in the inclusion group. Hens were housed in raised-wire cages with a stocking density of 870 cm²/bird. The adequate (100%) diet was based on corn and soybean meal and formulated based on the digestible (d) Lys and dAAs (dMet, dThr, dTrp, dTSAA, dIle, and dVal) to meet 100% of the current management guide recommendation. Variations in dAA/CP (95, 90, and 85% diets) were accomplished by reducing the 100% dAA by 5, 10, and 15%, respectively. All diets were supplemented with phytase at 500 phytase units (FTU)/kg. Data were analyzed using PROC GLM of SAS 9.4. There was a main effect of dAA/CP level on 85% diet where it had a lower mean hen-day egg production (HDEP, P < 0.01), egg mass (EM, P < 0.01), and higher feed conversion ratio (FCR, P < 0.001). Higher egg weight (P < 0.01) was observed in 95 and 100% dAA/CP level diets. However, Haugh unit (P < 0.01) and albumen height (P < 0.01) were higher in 85 and 90% diets. The inclusion of protease reduced the feed consumption (P = 0.0247), FCR for dozens of eggs (P = 0.0049) from 30 to 49 wk of age without affecting the HDEP or EM. Protease supplementation and dAA/CP level had an effect on the apparent ileal digestibility (AID) of CP (P = 0.019), Lys (P < 0.01), Thr (P < 0.01), Trp (P = 0.017), and Val (P < 0.01). Addition of protease significantly increased egg income (P = 0.033) and return on investment (P = 0.00223) from 30 to 37 wk of age. At 38 to 50 wk of age, dAA/CP level had a significant effect on egg income (P < 0.001), feed cost (P < 0.001), and return on investment (P < 0.001). This experiment indicates that the inclusion of protease in 90 and 95% lower dAA/CP diets could help improve the digestibility of CP, and key amino acids and maintain productive performance of corn and soybean meal-based diets in Hy-Line W-36 laying hen from 30 to 50 wk of age.

Effects of lysophospholipids and multi-enzymes on growth performance, antioxidant capacity, intestinal health, and cecal microflora of male cherry valley ducks

Improvement of nutrient utilization to promote growth performance is always pursued in poultry. In this study, a total of 360 1-d-old male ducklings was randomly assigned to 3 treatments in terms of diet treatment groups. Three treatments were as follows: basal diet (Con group) or basal diet supplemented with 300 mg/kg multi-enzymes (ENZ group) or 500 mg/kg lysophospholipids (LPL group). On day 42, ducks were slaughtered for samplings. The results revealed that supplementary LPL improved the body weight (BW) at day 14 and average daily gain (ADG) during days 1 to 14 and improved the feed conversion rate (FCR) for the overall period (P < 0.05) by improving nutrient utilization of dry matter and ether extract (P < 0.05) compared with the Con group. Dietary ENZ improved the FCR from days 15-42 and 1-42, and nitrogen utilization (P < 0.05) compared with the Con group. Jejunal villus height and villus height/crypt depth ratio were higher (P < 0.05) in the LPL group and tended to be higher (P < 0.1) in the ENZ group compared to the Con group. Supplementation with either LPL or ENZ reduced interleukin-1β concentration in jejunal mucus (P < 0.05). Both LPL and ENZ enhanced serum total superoxide dismutase activity (P < 0.05), whereas only supplementation with LPL elevated total antioxidant capacity (P < 0.05). In terms of cecal microbiota, microbial richness tended to be reduced by LPL, with low observed-OTUs and Chao1 (0.05 < P < 0.1). Supplementation with ENZ led to higher abundances of cellulolytic bacteria such as Fibrobacterota, [Eubacterium]_xylanophilum_group, and Bifidobacterium. Overall, both LPL and ENZ improved FCR, which may be relevant to ameliorative intestinal health, overall antioxidant ability, and cecal microbiome.

Multi-Omics Analysis of the Microbiome and Metabolome Reveals the Relationship Between the Gut Microbiota and Wooden Breast Myopathy in Broilers

Wooden breast (WB) is a widely prevalent myopathy in broiler chickens. However, the role of the gut microbiota in this myopathy remains largely unknown, in particular the regulatory effect of gut microbiota in the modulation of muscle metabolism. Totally, 300 1-day-old Arbor Acres broilers were raised until 49 days and euthanized, and the breast filets were classified as normal (NORM), mild (MILD), or severe wooden breast (SEV). Birds with WB comprised 27.02% of the individuals. Severe WB filets had a greater L* value, a* value, and dripping loss but a lower pH (P < 0.05). WB filets had abundant myofiber fragmentation, with a lower average myofiber caliber and more fibers with a diameter of <20 μm (P < 0.05). The diversity of the intestinal microflora was decreased in birds with severe WB, with decreases in Chao 1, and observed species indices. At the phylum level, birds with severe WB had a lower Firmicutes/Bacteroidetes ratio (P = 0.098) and a decreased abundance of Verrucomicrobia (P < 0.05). At the species level, gut microbiota were positively correlated with 131 digesta metabolites in pathways of glutamine and glutamate metabolism and arginine biosynthesis but were negatively correlated with 30 metabolites in the pathway of tyrosine metabolism. In plasma, WB induced five differentially expressed metabolites (DEMs), including anserine and choline, which were related to the severity of the WB lesion. The microbial-derived metabolites, including guanidoacetic acid, antiarol, and (2E)-decenoyl-ACP, which entered into plasma were related to meat quality traits and myofiber traits. In summary, WB filets differed in gut microbiota, digesta, and plasma metabolites. Gut microbiota respond to the wooden breast myopathy by driving dynamic changes in digesta metabolites that eventually enter the plasma.

Effect of marketable age on proximate composition and nutritional profile of breast meat from Cherry Valley broiler ducks

Marketable age is an important determinant of meat quality. Cherry Valley duck (SM3 medium) is the most efficient Pekin-type duck and is the most widely farmed breed globally. However, whether marketable age determines the meat quality of Cherry Valley ducks is not well documented. The objective of this study was to investigate the effect of marketable age on the proximate composition and nutritional profile of breast meat from Cherry Valley broiler ducks. Ducks at 28, 38, 42, and 45 days old were selected and slaughtered, and their proximate composition, cholesterol and essential mineral compositions, and amino acids and fatty acid profile of breast meat lipid were determined. The results showed higher protein content and lower intramuscular fat content were observed in the 38-day-old ducks than in the 28-day-old birds (P < 0.05). Additionally, 38-day-old ducks contained higher Fe and Mg contents (P < 0.05), whereas 28-day-old birds had higher Zn and Ca contents (P < 0.05). The essential amino acid content in 38-day-old was about 95.29 g/kg, higher than that in 28-day-old birds (P < 0.05). The contents of C20:5 n-3, omega-6 polyunsaturated fatty acids, and polyunsaturated fatty acids were the highest in 38-day-old birds (P < 0.05), whereas the content of C20:4 n-6, DHA (C22:6 n-3), and saturated fatty acids in 28-day-old birds was the lowest (P < 0.05). Finally, a comprehensive evaluation model of multiple traits was developed by applying principal component analysis, and the meat nutrition of 38-day-old ducks was identified as the optimal. Taken together, the meat of 38-day-old ducks had an advantage in proximate composition, minerals content, essential amino acids, and fatty acids, and 38 d might be recommended as an appropriate marketable age to provide duck meat of high nutrition value.

Impact of Microbial Protease Enzyme and Dietary Crude Protein Levels on Growth and Nutrients Digestibility in Broilers over 15-28 Days

Simple Summary

Protein is considered as the most expensive nutrient in animal diet and requires exogenous proteolytic enzymes for proper digestion in all living organisms. Thus, the present study evaluated different crude protein levels (CP) with or without exogenous protease in broilers diet over 15–28 days on their growth and nutrient digestibility. Based on the obtained findings, it is recommended a reduction in protein contents of diets from 21 to 19% when the protease enzyme is supplemented, to produce a beneficial impact on the growth and digestibility of broilers and also to reduce feeding costs.

Abstract

In this trial, a 3 × 2 factorial design with different dietary crude protein levels (CP, 17, 19 and 21%) and two levels of exogenous protease (0 and 30,000 IU/kg) was used. A total of 540 two-week old broilers (Ross-308) was randomly allocated to experimental diets over 15–28 days of age. The interaction between dietary protein levels and enzyme supplementation showed that body weight gain was significantly (p < 0.05) higher in birds fed CP-19 (1114.7 g) and CP-21 (1108.8 g) with enzymes supplementation. Feed intake was higher (p < 0.05) in broilers fed with CP-17 than CP-19 with supplementation of the protease enzyme. Results also revealed that the feed conversion ratio (FCR) was significantly (p < 0.05) improved in birds fed with CP-19 and CP-21 and protease supplementation. Total tract N retention was lower (p < 0.05) in birds fed CP-17 with no enzyme than the other dietary groups. Similarly, the gross energy (GE) was significantly (p < 0.05) lower in birds fed CP-17 with or without the protease enzyme. Abdominal fat was higher (p < 0.05) in CP-17 (0.96%) without the protease enzyme. It was concluded that a diet at 19% CP with the protease enzyme improved the performance and nutrient digestibility in broilers over 15–28 days.

Effects of Soy Protein Concentrate in Starter Phase Diet on Growth Performance, Blood Biochemical Indices, Carcass Traits, Immune Organ Indices and Meat Quality of Broilers

Soybean meal (SBM) is high in antinutritional factors (ANFs), which is not conducive to the starter growth of broilers. The purpose of this study was to investigate the effects of soy protein concentrate (SPC) in starter diet on growth performance, carcass traits, meat quality, immune organ indices and blood biochemical indices of broilers. A total of 384 1-day-old Arbor Acres (AA) male broilers (46.05 ± 0.37 g) with similar body weight were randomly divided into 4 groups with 8 replicates in each group and 12 broilers in each replicate. The experiment was divided into three phases: in starter phase (1-10 d), birds were fed a corn-SBM-based basal mash diet (control) and the basal diet was supplemented with SPC at 4% (SPC4), 8% (SPC8), 12% (SPC12). In the grower phase (11-21 d) and the finisher phase (22-42 d), the birds in all four treatment groups were fed the same diets. The results showed that the body weight was significantly increased in the SPC8 and SPC12 groups of broilers at 10 d and 42 d (p < 0.05). The average daily gain was significantly increased in the SPC12 group of broilers at 1-10 d and 1-42 d (p < 0.05). The average daily feed intake was significantly increased in the SPC8 and SPC12 groups of broilers at 1-10 d (p < 0.05). The feed conversion rates at 1-42 d (p = 0.055) tended to decline in the SPC12 group. The carcass yield and the thymus indices were significantly increased in the SPC12 group of broilers at 42 d (p < 0.05). Alanine aminotransferase (ALT)/ aspartate aminotransferase (AST) tended to decline in SPC12 group at 10 d (p = 0.055) and total protein (TP) tended to increase in the SPC12 group at 42 d (p = 0.080). The contents of total cholesterol (T-CHO) and high-density lipoprotein (HDL) were significantly elevated in the SPC12 group of broilers at 42 d (p < 0.05). In conclusion, dietary inclusion of 12% SPC as a starter diet can be recommended due to the positive effects on broilers.

Protease supplementation attenuates the intestinal health damage caused by low-protein diets in Pekin ducks

The objective of this study was to investigate the effects of low-protein diets with low digestibility of feed ingredients on intestinal damage and to explore whether the protease supplementation can alleviate the damage in Pekin ducks. A total of 576 Pekin ducklings (6 replicate pens, 16 ducks/pen) were randomly assigned to 6 dietary treatments (3 × 2 factorial arrangement) in a randomized complete block design. Factors were CP levels (13.5%, 15.5%, and 17.5%) and protease (0 or 20,000U/kg). Compared with the diets containing 17.5% CP, low-protein diets (13.5% CP) showed suppressed (P < 0.05) growth performance and feed intake (FI); reduced (P < 0.05) serum-free arginine, isoleucine, leucine, methionine, phenylalanine, valine, and proline as well as the cecal acetate and propionate concentration; increased (P < 0.05) plasma and ileal mucosal tumor necrosis factor-α (TNF-α) concentration; and downregulated (P < 0.05) mRNA expression of TNF-α, nuclear transcription factor-κb, interferon gamma, and Occludin in ileal mucosa. Irrespective of the dietary CP levels, protease supplementation significantly increased (P < 0.05) the serum-free glutamic acid concentration while decreasing (P < 0.05) the plasma endotoxin, IL-6, and the cecal isovalerate concentration. A significant interactive effect was observed between low-protein diets and protease supplementation (P < 0.05) on serum-free arginine concentration, the ratio of ileal villus height to crypt depth, and the IL-6 concentration in ileal mucosa. These results indicated that low-protein diets could damage intestinal integrity to induce systemic inflammation response and at last to suppress growth performance. Protease supplementation could partly attenuate the negative effects on gut health caused by low-protein diets in Pekin ducks.