Review: Physiological growth trend of current meat broilers and dietary protein and energy management approaches for sustainable broiler production

Effects of finisher diet nutrients density and slaughter age on energy and protein efficiency, productive and economic performance and meat quality of broilers

BACKGROUND

The current broilers have been greatly optimized for weight gain and breast yield, which necessitates the provision of nutrients-dense diets for maximum potential.

OBJECTIVES

The current study aimed to evaluate the effect of finisher diet nutrients density (ND) on energy and protein efficiency, productive and economic performance and breast meat quality of broilers raised until different slaughter age.

METHODS

A total of 600 23-day-old broiler male chicks (Cobb-500) were assigned to 10 treatments with six replicates and 10 birds each. Experimental treatments were included factorial arrangement of five increment (2.5%) levels of finisher diet ND (92.5%, 95%, 97.5%, 100% and 102.5% as strain recommendation) and slaughtered at 38 or 46 days of age. The relative difference in the energy level of experimental diets was used to increase ND levels at the same ratio.

RESULTS

Feed intake (FI) and breast meat quality traits exception water holding capacity (WHC) were not affected by finisher diet ND. In response to increasing finisher diet ND, energy and protein efficiency, productive traits, bio-economic index (BEI) and breast relative weight (BRW) linearly improved. However, residual feed intake and breast meat WHC improved with a quadratic trend. By using broken-line regression analysis, the optimum dietary ND was obtained at 97.5%-102% of strain recommendation. Energy and protein efficiency, feed conversion ratio and BEI deteriorated by prolonging rearing period. The BRW, meat lightness (L*), redness (a*), hue angle (h*) and WHC values for the birds slaughtered at 46 days of age were significantly higher, and cooking loss was lower than those slaughtered at 38 days old.

CONCLUSIONS

Broilers during the finisher period are not able to regulate their FIs with diet ND. The energy and protein efficiency, productive and economic performance were reduced when broilers were fed diluted diet or the rearing period was prolonged.

Empowering veterinary clinical diagnosis in industrial poultry production by ambient mass spectrometry and chemiometrics: a new approach for precise poultry farming

Untargeted metabolomic profiling, by ambient mass spectrometry and chemometric tools, has made a dramatic impact on human disease detection. In a similar vein, this study attempted the translation of this clinical human disease experience to farmed poultry for precise veterinary diagnosis. As a proof of principle, in this diagnostic/prognostic study, direct analysis in real-time high resolution mass spectrometry (DART-HRMS) was used in an untargeted manner to analyze fresh tissues (abdominal fat, leg skin, liver, and leg muscle) of pigmented and non-pigmented broilers to investigate the causes of lack of pigmentation in an industrial poultry farm. Afterwards, statistical analysis was applied to the DART-HRMS data to retrieve the molecular features that codified for 2 broiler groups, that is, properly pigmented and non-pigmented broilers. Higher abundance of oxidized lipids, high abundance of oxidized bile derivatives, and lower levels of tocopherol isomers (Vitamin E) and retinol (Vitamin A) were captured in nonpigmented than in pigmented broilers. In addition, conventional rapid analyses were used: 1) color parameters of the tissues of pigmented and non-pigmented broilers were measured to rationalize the color differences in abdominal fat, leg skin and leg muscle, and 2) macronutrients were determined in broiler leg muscle, to capture a detailed picture of the pathology and exclude other possible causes. In this study, the DART-HRMS system performed well in retrieving valuable chemical information from broilers that explained the differences between the 2 groups of broilers in absorption of xanthophylls and the subsequent lack of proper broiler pigmentation in affected broilers. The results suggest this technology could be useful in providing near real-time feedback to aid in veterinary decision-making in poultry farming.

A Meta-Analysis of the Effects of Dietary Yeast Mannan-Rich Fraction on Broiler Performance and the Implication for Greenhouse Gas Emissions from Chicken Production

Dietary supplementation of yeast-derived mannan-rich fraction (MRF) could improve the gastrointestinal health and production efficiency of broilers, and, consequently, lower the environmental impacts of chicken production. The objective of this meta-analysis was to quantify the retrospective effects of feeding MRF (Actigen®, Alltech Inc., Nicholasville, KY) on the production performance of broilers. The meta-analysis database included 27 studies and consisted of 66 comparisons of MRF-supplemented diets vs. basal (i.e., negative control) and antibiotic-supplemented (i.e., positive control) diets. A total of 34,596 broilers were involved in the comparisons and the average final age of the birds was 35 days. Additionally, the impact of feeding MRF on the carbon footprint (feed and total emission intensities) of chicken production was evaluated using the meta-analysis results of broiler performance (MRF vs. basal diets) to develop a scenario simulation that was analyzed by a life cycle assessment (LCA) model. A database of all trials (MRF vs. basal and antibiotic diets) indicated that feeding MRF increased (p < 0.01) average daily feed intake (ADFI; +3.7%), final body weight (FBW; +3.5%), and average daily gain (ADG; 4.1%) and improved (p < 0.01) feed conversion ratio (FCR; -1.7%) without affecting (p > 0.05) mortality. A subdatabase of MRF vs. basal diets indicated that dietary MRF increased ADFI (+4.5%), FBW (+4.7%), and ADG (+6.3%) and improved FCR (-2.2%) and mortality (-21.1%). For the subdatabase of MRF vs. antibiotic diets, both treatments exhibited equivalent effects (p > 0.05) on broiler performance parameters, suggesting that MRF could be an effective alternative to in-feed antibiotics. Subgroup analysis revealed that different study factors (year of study, breed/strain, production challenges, and MRF feeding duration) influenced the effect of dietary MRF on broiler performance. Simulated life cycle analysis (LCA) indicated that feeding MRF decreased feed and total emission intensities, on average, by -2.4% and -2.1%, respectively. In conclusion, these results demonstrate that dietary MRF is an effective nutritional solution for improving broiler performance, an effective alternative to in-feed antibiotic growth promoters, and reduces the environmental impact of poultry meat production.

Physical and Chemical Characteristics of Droppings as Sensitive Markers of Chicken Health Status

The aim of this study was to analyze the physical and chemical characteristics of chicken droppings (n = 73), which were collected during different age periods and classified by visual inspection into normal (N) and abnormal (A). Significant differences were found in the texture, pH, dry matter (DM), fatty acids (FAs), short-chain fatty acids (SCFAs), and volatile compounds (VCs) between the tested dropping groups (p ≤ 0.05). The age period of the chicken had a significant influence on the color coordinates, texture, pH, DM, and SCFA contents in N and A as well as on all FAs content in N (p ≤ 0.05). Droppings from the N group had a harder texture, lower values of a* and b* color coordinates, higher DM content, higher level of linoleic FA, and lower level of α-linolenic FA than the droppings from the A group in each age period (p ≤ 0.05). The predominant SCFA was acetic acid, the content of which was significantly lower in the N group compared to that of the A group. The alcohol and organic acid contents were the highest in most of the A group at different age periods, while ketones dominated in the N and A groups. In conclusion, the majority of the tested dropping characteristics were influenced by the age period. While certain characteristics demonstrate differences between N and A, a likely broader range of droppings is required to provide more distinct trends regarding the distribution of characteristics across different droppings.

Age-Related Changes in Hepatic Lipid Metabolism and Abdominal Adipose Deposition in Yellow-Feathered Broilers Aged from 1 to 56 Days

The objective of this study was to evaluate the age-related changes in hepatic lipid metabolism, adipocyte hyperplasia, hypertrophy, and lipid metabolism in the abdominal adipose tissue of yellow-feathered broilers. Blood, liver, and abdominal adipose samples were collected on days 1, 7, 14, 21, 28, 35, 42, 49, and 56. Body, liver, and abdominal weight increased (p < 0.05) with age-related changes. The triacylglycerol content peaked on day 14, and total cholesterol content peaked on day 56. The adipocyte diameter and area peaked on day 56, and total DNA content peaked on day 7. The age-related changes in hepatic lipogenesis-related gene (ChREBP, SREBP-1c, ACC, FAS, SCD1) expression mainly occurred during days 1 to 21, hepatic lipolysis-related gene (CPT1, LPL, ApoB) expression mainly occurred during days 1 to 14, and abdominal adipose-deposition-related gene (PPARα, CPT1, LPL, PPARγ, C/EBPβ) expression occurred during days 1 to 14. These results demonstrated a dynamic pattern of hepatic lipid metabolism and abdominal adipose deposition in yellow-feathered broilers, which provides practical strategies to regulate hepatic lipid metabolism and reduce abdominal adipose deposition in yellow-feathered broilers.

Leg disorders in broiler chickens: a review of current knowledge

Ensuring improved leg health is an important prerequisite for broilers to achieve optimal production performance and welfare status. Broiler leg disease is characterized by leg muscle weakness, leg bone deformation, joint cysts, arthritis, femoral head necrosis, and other symptoms that result in lameness or paralysis. These conditions significantly affect movement, feeding and broiler growth performance. Nowadays, the high incidence of leg abnormalities in broiler chickens has become an important issue that hampers the development of broiler farming. Therefore, it is imperative to prevent leg diseases and improve the health of broiler legs. This review mainly discusses the current prevalence of broiler leg diseases and describes the risk factors, diagnosis, and prevention of leg diseases to provide a scientific basis for addressing broiler leg health problems.

Enzymolytic soybean meal improves growth performance, economic efficiency and organ development associated with cecal fermentation and microbiota in broilers offered low crude protein diets

The objective of this experiment was to determine the effect of low crude protein (CP) diets containing increasing amounts of enzymolytic soybean meal (ESBM) on growth performance, economic benefit and organ development and the role of cecal fermentation and microbiota in broilers. A total of 360 one-day-old Arbor Acres chicks were randomly allocated into 6 groups with 6 replicates and 10 chicks each. The six dietary treatments consisted of a standard high-CP diet (PC), a low-CP diet (NC), and an NC diet with 0.5, 1.0, 1.5%, or 2.0% ESBM. The experiment lasted for 42 days. Compared to PC, NC showed decreased (p < 0.05) average daily gain (ADG) in broilers from 22 to 42 days and from 1 to 42 days, while increasing levels of ESBM quadratically increased (p < 0.05) ADG from 1 to 42 days. Feed cost and total revenue in the NC were lower (p < 0.05) than that in the PC, while supplementation with ESBM in the NC linearly increased (p < 0.05) net profit and economic efficiency in broilers. There were significant differences (p < 0.05) in the liver, proventriculus and gizzard indices between the PC and NC groups, and supplementation with ESBM linearly increased (p < 0.05) the relative weights of liver, pancreas, proventriculus and gizzard in broilers at 42 days of age. The PC group had a higher cecal acetic acid concentration at 21 days and propionic acid concentration at both 21 and 42 days than the NC group (p < 0.05). Cecal acetic acid and propionic acid concentrations linearly increased (p < 0.05) with increasing levels of ESBM in broilers at 42 days of age. No significant differences in ACE, Chao1, Shannon and Simpson indices were observed among groups (p > 0.05), while the cecal abundances of Bacteroides, Faecalibacterium and Clostridium IV increased (p < 0.05) with the increasing level of ESBM in the low-CP diets. In conclusion, feeding ESBM improved economic efficiency, digestive organ development, cecal fermentation and microbial community composition, and up to 2.0% ESBM addition had no negative effect on the growth performance in broilers fed low CP diets.

A succession of pulmonary microbiota in broilers during the growth cycle

Respiratory health problems in poultry production are frequent and knotty and thus attract the attention of farmers and researchers. The breakthrough of gene sequencing technology has revealed that healthy lungs harbor rich microbiota, whose succession and homeostasis are closely related to lung health status, suggesting a new idea to explore the mechanism of lung injury in broilers with pulmonary microbiota as the entry point. This study aimed to investigate the succession of pulmonary microbiota in healthy broilers during the growth cycle. Fixed and molecular samples were collected from the lungs of healthy broilers at 1, 3, 14, 21, 28, and 42 d of age. Lung tissue morphology was observed by hematoxylin and eosin staining, and the changes in the composition and diversity of pulmonary microbiota were analyzed using 16S rRNA gene sequencing. The results showed that lung index peaked at 3 d, then decreased with age. No significant change was observed in the α diversity of pulmonary microbiota, while the β diversity changed regularly with age during the broilers' growth cycle. The relative abundance of dominant bacteria of Firmicutes and their subordinate Lactobacillus increased with age, while the abundance of Proteobacteria decreased with age. The correlation analysis between the abundance of differential bacteria and predicted function showed that dominant bacteria of Firmicutes, Proteobacteria and Lactobacillus were significantly correlated with most functional abundance, indicating that they may involve in lung functional development and physiological activities of broilers. Collectively, these findings suggest that the lung has been colonized with abundant microbiota in broilers when they were just hatched, and their composition changed regularly with day age. The dominant bacteria, Firmicutes, Proteobacteria, and Lactobacillus, play crucial roles in lung function development and physiological activities. It paves the way for further research on the mechanism of pulmonary microbiota-mediated lung injury in broilers.

The assessment of serum trace element levels as the diagnostic biomarkers of functional state of broiler chickens

Background and Aim

Elemental analysis is a useful technique for predicting metabolic disorders in broiler chickens. Elemental imbalances are also important for the development of new methods to diagnose the health status of birds that can be implemented on a farm-wide scale. This study aimed to identify elemental markers related to pre-nosological diagnoses of metabolic disorders in broiler chickens.

Materials and Methods

We compared birds given high-protein, high-carbohydrate, and high-fat diets. A control group received the standard diet recommended by the All-Russian Research and Technological Institute of Poultry, while experimental Group I received a diet with high-protein content, Group II received a diet with high-carbohydrate content, and Group III received a diet with high-fat content. At the end of the experiment, blood samples were taken for biochemical and elemental analysis. Biochemical analysis was carried out using an automated biochemical analyzer, and the levels of trace elements in the serum were assessed using inductively coupled plasma spectrometry.

Results

We found that the high-protein diet was accompanied by a decrease in chicken body weight, cholesterol, and several elements (i.e., P, Cr, Cu, Zn, and B) as well as an increase in the levels of Ca, Co, and Si. The high-carbohydrate diet led to a significant increase in glucose levels as well as a decrease in the levels of albumin, triglycerides, and Cr, Mn, Se, I, and Cu. Finally, the high-fat diet led to an increase in body weight, glucose, cholesterol, triglycerides, and the elements Cu, Zn, and Si as well as a decrease in the levels of Mg, Cr, and Fe.

Conclusion

The determination of the levels of trace elements such as Co, Cr, Mn, Fe, and Cu in chicken blood serum may be an important indicator of the state of protein, carbohydrate, and lipid metabolism of poultry stock.

Review: Current challenges in poultry nutrition, health, and welfare

The poultry industry has benefited greatly from advances in genetics, nutrition, housing and management strategies. Geneticists have made welfare and health traits important components of selection programs, and in general, modern, high-producing poultry are healthier than 30 years ago. However, increased productivity means that the birds are closer to their physiological limits, and nutrition, environment and management have become increasingly important. The move away from in-feed antibiotic growth promotors has resulted in challenges in maintaining gut health and consequently, bird performance. However, as the industry adapts to production without the use of antibiotic growth promotors, long-term benefits may be realized due to a reduction in antimicrobial resistance. Intensive selection for meat yield and efficiency are associated with an increased risk of muscle myopathies that affect bird health and meat quality. As genetic selection increased broiler production traits, it became necessary to restrict parent stock nutrient intake in order to prevent excessive muscle and fat deposition, reduce metabolic disease, and maintain ovarian control. With continued selection for broiler production traits, the degree of restriction implemented has become a welfare issue. Additionally, recent research suggests that highly efficient broiler lines may have limited fat deposition and therefore energy reserves to support sexual maturation and egg production, especially if typical broiler breeder BW targets are maintained. A re-examination of broiler breeder feeding programs is necessary to maintain productivity and welfare. Modern laying hens are capable of laying cycles in excess of 100 weeks of age. This has reduced the use of stress-inducing forced molting programs and reduces the total number of hens needed to meet the demand for egg production. The important role of the skeletal system in eggshell deposition demands that skeletal development during rearing be carefully managed to avoid shell and skeletal problems at the end of the production cycle. As the production potential of modern poultry continues to increase through genetic and genomic selection, even greater care must be paid in order to maintain bird health and welfare. The poultry industry has successfully faced many challenges in the past and is likely to overcome the existing challenges as well.

Transcriptome and co-expression network analysis reveals the molecular mechanism of inosine monophosphate-specific deposition in chicken muscle

The inosine monophosphate (IMP) content in chicken meat is closely related to muscle quality and is an important factor affecting meat flavor. However, the molecular regulatory mechanisms underlying the IMP-specific deposition in muscle remain unclear. This study performed transcriptome analysis of muscle tissues from different parts, feeding methods, sexes, and breeds of 180-day-old Jingyuan chickens, combined with differential expression and weighted gene co-expression network analysis (WGCNA), to identify the functional genes that regulate IMP deposition. Out of the four comparison groups, 1,775, 409, 102, and 60 differentially expressed genes (DEGs) were identified, of which PDHA2, ACSS2, PGAM1, GAPDH, PGM1, GPI, and TPI1 may be involved in the anabolic process of muscle IMP in the form of energy metabolism or amino acid metabolism. WGCNA identified 11 biofunctional modules associated with IMP deposition. The brown, midnight blue, red, and yellow modules were strongly correlated with IMP and cooking loss (p < 0.05). Functional enrichment analysis showed that glycolysis/gluconeogenesis, arginine and proline metabolism, and pyruvate metabolism, regulated by PYCR1, SMOX, and ACSS2, were necessary for muscle IMP-specific deposition. In addition, combined analyses of DEGs and four WGCNA modules identified TGIF1 and THBS1 as potential candidate genes affecting IMP deposition in muscle. This study explored the functional genes that regulate muscle development and IMP synthesis from multiple perspectives, providing an important theoretical basis for improving the meat quality and molecular breeding of Jingyuan chickens.

The Effect of Encapsulated Propyl Propane Thiosulfonate (PTSO) on Apparent Ileal Digestibility and Productive Performance in Broiler Chickens

This study analyzed the effects of different dietary doses of encapsulated propyl propane thiosulfonate (Pe-PTSO) on the apparent ileal digestibility (AID) of nutrients and productive performance in broilers. A total of 100 one-day-old Cobb 500 were housed in battery cages for 20 days. At 10 days of age, the birds were assigned to one of five diets: negative control (P0), 250 mg/kg of Pe-PTSO (P250), 500 mg/kg of Pe-PTSO (P500), 750 mg/kg of Pe-PTSO (P750), and positive control, nicarbazin-narasin (ION). Titanium dioxide was the external marker, which was added to the diets from day 17 to 20. In the birds fed the P250 diet, there was a significant difference (p ≤ 0.05) in the AID values for amino acids and energy compared to those that consumed the P0 diet. Furthermore, the P250 diet significantly increased (p ≤ 0.05) the average daily weight gain compared to the P0 diet. No significant differences were observed between treatments in average daily feed intake and feed conversion ratio. In summary, the inclusion of 250 mg of encapsulated PTSO per kg in broiler chickens diet improved the digestibility of amino acids and energy, as well as weight gain.

The Relationship between Performance, Body Composition, and Processing Yield in Broilers: A Systematic Review and Meta-Regression

This study aims to model the relationship among performance, whole body composition, and processing yield through meta-regression. Scientific papers found in Scopus and Google Scholar were included if they reported results and variability values of an actual experiment in the three mentioned groups of variables using a single broiler genetic line. Weighted mean effect sizes were determined with a random model, the risk of bias was determined, and heterogeneity was considered an indicator of usefulness. Meta-regressions considered the effect sizes of the response variable and the percent change in one or more variables as predictors. A 78-row database was built from 14 papers, including nine factors tested on 22,256 broilers. No influencing bias was found, and the data was determined useful. Meta-regressions showed that the changes in body weight gain (BWG) are inversely related to the effects in feed conversion ratio (FCR) (p < 0.001) and that the changes in FCR and effects in protein-to-fat gain (PFG) are directly related (p < 0.001). The changes in PFG and the effects on carcass conformation or the market value of birds are directly related (p < 0.001). In conclusion, body composition predicts carcass conformation and its market value, supporting its use to predict the economic value of broilers.

Safety Evaluation of a Novel Algal Feed Additive for Poultry Production

Feed additives are critical components for poultry health and the economic viability of antibiotic-free poultry production. The aim of the present study is to evaluate the safety of a novel algal-derived feed additive, a dried biomass powder produced from Chlamydomonas reinhardtii strain crAL082, modified to express an N-acetylmuramoyl-L-alanine amidase (EC 3.5.1.28) and a lysozyme-type enzyme (EC 3.2.1.17). A 42-day oral toxicity study showed that the crAL082 dried biomass powder was fully tolerated by broiler chicken based on the lack of detrimental effects found in performance, mortality, hematology, blood clinical chemistry, and histopathologic results compared with those of a nontreated control group, resulting in a "No Observed Adverse Effect Level" of 5000 ppm, the highest dose tested. The study demonstrates the first-ever safety result of a C. reinhardtii microalgae dried biomass powder used as a feed additive in broiler chickens. Furthermore, safety is shown for the two additional enzymes expressed within the C. reinhardtii crAL082 strain and ingested by the birds.

L-serine improves lipid profile, performance, carcass weight and intestinal parameters in feed restricted broiler chickens during the hot-dry season

The study evaluated effects of L-serine on lipid profile, performance, carcass weight and small intestinal parameters in heat-stressed broiler chickens subjected to feed restriction. Broiler chickens were divided into four groups, comprising 30 each. Group 1, feed restriction (FR); Group 2, feed restriction + L-serine (200 mg/kg) (FR + L-serine); Group 3, ad libitum (AL); Group 4, ad libitum + L-serine (200 mg/kg) (AL + L-serine). L-serine was administered orally from days 1 to 14, and feed restriction was performed on days 7-14. Serum harvested from blood samples on days 21, 28 and 35 was evaluated for lipid profile. Feed and water intake, live weight gain, organ and carcass weight were measured. At 35 days old, broiler chickens (n = 7) per group were sacrificed to evaluate small intestinal morphology. Temperature-humidity index in the pen (30.88 ± 0.81) was above thermoneutral zone, indicating that chickens were subjected to heat stress. Concentrations of low-density lipoprotein, total cholesterol and total triglycerides were lower (p < 0.05), while higher concentration of high-density lipoprotein was recorded in L-serine groups than in the controls. Feed intake and live weight gain on day 35 in L-serine groups were higher (p < 0.05) than in controls. In L-serine groups, liver, spleen, pancreas and heart weight were higher, but abdominal fat was lower than in FR and AL groups. Villus height:crypt height ratio and area of villus surface were highest in L-serine groups than any other group. In conclusion, L-serine decreased low-density lipoprotein, increased feed intake, live weight, organ and carcass weight, villus height:crypt height ratio and villus surface area.

Evaluation of Hepatic Detoxification Effects of Enteromorpha prolifera Polysaccharides against Aflatoxin B1 in Broiler Chickens

Aflatoxin B₁ (AFB₁) is a major risk factor in animal feed. Seaweed (Enteromorpha prolifera)-derived polysaccharides (SDP) are natural antioxidants with multiple biological functions, which may have an in vivo detoxification effect on AFB₁. The current study aimed to evaluate whether SDP could mitigate AFB₁-induced hepatotoxicity in broilers. A total of 216 chickens (male, 5 weeks old) were randomly allocated to three groups with differing feeding patterns, lasting 4 weeks: (1) control group (CON, fed a basal diet); (2) AFB₁ group (fed a basal diet mixed with 0.1 mg/kg AFB₁); and (3) AFB₁ + SDP group (AFB₁ group + 0.25% SDP). The results showed that dietary SDP improved the liver function-related biochemical indicators in serum, and reversed the increase in relative liver weight, hepatic apoptosis and histological damage of broilers exposed to AFB₁. SDP treatment also reduced the activity and mRNA expression of phase I detoxification enzymes, while increasing the activity and mRNA expression of phase II detoxification enzymes in the livers of AFB₁-exposed broilers, which was involved in the activation of p38 mitogen-activated protein kinase (p38MAPK)/nuclear factor erythroid 2-related factor 2 (Nrf2) signaling. In conclusion, dietary SDP alleviated AFB₁-induced liver injury of broilers through inhibiting phase I detoxification enzymes and upregulating p38MAPK/Nrf2-mediated phase II detoxification enzymes pathway.

Food Industry Byproducts as Starting Material for Innovative, Green Feed Formulation: A Sustainable Alternative for Poultry Feeding

Rising global populations and enhanced standards of living in so-called developing countries have led to an increased demand of food, in particular meat, worldwide. While increasing the production of broiler meat could be a potential solution to this problem, broiler meat is plagued by health concerns, such as the development of antimicrobial resistance and lower meat quality. For this reason, the supplementation of poultry feed with vitamins and antioxidant compounds, such as polyphenols, has become an attractive prospect for research in this sector. Such supplements could be obtained by extraction of agricultural byproducts (in particular, grape pomaces and artichoke leaves and bracts), thus contributing to reductions in the total amount of waste biomass produced by the agricultural industry. In this review, the effects of poultry feed supplementation with bioactive extracts from grape pomace (skins and/or seeds), as well as extracts from artichoke leaves and bracts, were explored. Moreover, the various methods that have been employed to obtain extracts from these and other agricultural byproducts were listed and described, with a particular focus on novel, eco-friendly extraction methods (using, for example, innovative and biocompatible solvents like Deep Eutectic Solvents (DESs)) that could reduce the costs and energy consumption of these procedures, with similar or higher yields compared to standard methods.

Relationship among Sex, Skin Color, and Production Parameters of Broiler in Pectoral Myopathies

Breast anomalies in broilers, especially wooden breast (WB) and spaghetti meat (SM), cause high economic losses to the poultry meat sector. In order to identify the parameters that have a causal effect and to reduce the incidence of these myopathies, 141,792 broilers were analyzed in a total of 1477 batches using a visual grading system. The relationship among productive parameters such as the feed conversion ratio, live weight, growth rate, and mortality, was evaluated. Effects due to skin color (white vs. yellow), broiler sex (male, female, and mixed groups), feed presentation (grain vs. mash), and veterinary treatments (treated vs. untreated) were also included in the statistical study. Live weight was observed to have a significant effect (p < 0.001) on WB incidence, which increased by 1.11 for each 100 g of weight. Weight did not significantly affect the incidence of SM. Males had a higher incidence of WB and a lower incidence of SM than females. The incidence of both myopathies varied between samples that turned out to be significantly affected by some of the variables considered in the model, such as grain feeding and the feed conversion ratio. Controlling these factors in the broiler production could help to reduce the incidence of WB and SM.

Noninvasive fecal metabolic profiling for the evaluation of characteristics of thermostable lactic acid bacteria, Weizmannia coagulans SANK70258, for broiler chickens

Weizmannia coagulans SANK70258 is a spore-forming thermostable lactic acid bacterium and an effective probiotic for the growth of livestock animals, but its growth-promoting mechanism remains unclear. Here, the composition of fecal metabolites in broilers continuously administered with W. coagulans SANK70258 was assessed under a regular program with antibiotics, which was transiently given for 6 days after birth. Oral administration of W. coagulans to broiler chicks tended to increase the average daily gain of body weights thereafter. The composition of fecal metabolites in the early chick stage (Day 10 after birth) was dramatically altered by the continuous exposure. The levels of short-chain fatty acids (SCFAs) propionate and butyrate markedly increased, while those of acetate, one of the SCFAs, and lactate were reduced. Simultaneously, arabitol, fructose, mannitol, and erythritol, which are carbohydrates as substrates for gut microbes to produce SCFAs, also increased along with altered correlation. Correlation network analyses classified the modularity clusters (|r| > 0.7) among carbohydrates, SCFAs, lactate, amino acids, and the other metabolites under the two conditions. The characteristic diversities by the exposure were visualized beyond the perspective associated with differences in metabolite concentrations. Further, enrichment pathway analyses showed that metabolic composition related to biosynthesis and/or metabolism for SCFAs, amino acids, and energy were activated. Thus, these observations suggest that W. coagulans SANK70258 dramatically modulates the gut metabolism of the broiler chicks, and the metabolomics profiles during the early chick stages may be associated with growth promotion.

Transcriptome Analysis Reveals the Differentially Expressed Genes Associated with Growth in Guangxi Partridge Chickens

The Guangxi Partridge chicken is a well-known chicken breed in southern China with good meat quality, which has been bred as a meat breed to satisfy the increased demand of consumers. Compared with line D whose body weight is maintained at the average of the unselected group, the growth rate and weight of the selected chicken group (line S) increased significantly after breeding for four generations. Herein, transcriptome analysis was performed to identify pivotal genes and signal pathways of selective breeding that contributed to potential mechanisms of growth and development under artificial selection pressure. The average body weight of line S chickens was 1.724 kg at 90 d of age, which showed a significant increase at 90 d of age than line D chickens (1.509 kg), although only the internal organ ratios of lung and kidney changed after standardizing by body weight. The myofiber area and myofiber density of thigh muscles were affected by selection to a greater extent than that of breast muscle. We identified 51, 210, 31, 388, and 100 differentially expressed genes (DEGs) in the hypothalamus, pituitary, breast muscle, thigh muscle, and liver between the two lines, respectively. Several key genes were identified in the hypothalamus-pituitary-muscle axis, such as FST, THSB, PTPRJ, CD36, PITX1, PITX2, AMPD1, PRKAB1, PRKAB2, and related genes for muscle development, which were attached to the cytokine–cytokine receptor interaction signaling pathway, the PPAR signaling pathway, and lipid metabolism. However, signaling molecular pathways and the cell community showed that elevated activity in the liver of line S fowl was mainly involved in focal adhesion, ECM-receptor interaction, cell adhesion molecules, and signal transduction. Collectively, muscle development, lipid metabolism, and several signaling pathways played crucial roles in the improving growth performance of Guangxi Partridge chickens under artificial selection for growth rate. These results support further study of the adaptation of birds under selective pressure.

The "ideal protein" concept is not ideal in animal nutrition

Amino acids (AAs) are required for syntheses of proteins and low-molecular-weight substances with enormous physiological importance. Since 1912, AAs have been classified as nutritionally essential amino acids (EAAs) or nonessential amino acids (NEAAs) for animals. EAAs are those AAs that are either not synthesized or insufficiently synthesized de novo in the organisms. It was assumed that all NEAAs (now known as AAs that are synthesizable in animal cells de novo [AASAs]) were formed sufficiently in animals and were not needed in diets. However, studies over the past three decades have shown that sufficient dietary AASAs (e.g. glutamine, glutamate, glycine, and proline) are necessary for the maximum growth and optimum health of pigs, chickens, and fish. Thus, the concept of "ideal protein" (protein with an optimal EAA pattern that precisely meets the physiological needs of animals), which was originally proposed in the 1950s but ignored AASAs, is not ideal in animal nutrition. Ideal diets must provide all physiologically and nutritionally essential AAs. Improved patterns of AAs in diets for swine and chickens as well as zoo and companion animals have been proposed in recent years. Animal-sourced feedstuffs supply abundant EAAs and AASAs (including glutamate, glutamine, glycine, proline, 4-hydroxyproline, and taurine) for diets of swine, poultry, fish, and crustaceans to improve their growth, development, reproduction, and health, while sustaining global animal production. Nutritionists should move beyond the "ideal protein" concept to consider optimum ratios and amounts of all proteinogenic AAs in diets for mammals, birds, and aquatic animals, and, in the case of carnivores, also taurine.

Soybean vs. Pea Bean in the Diet of Medium-Growing Broiler Chickens Raised under Semi-Intensive Conditions of Inner Mediterranean Areas: Growth Performance and Environmental Impact

The effects of Glycine max L. (SOY) vs. Pisum sativum L. (PEA) in the diet were investigated on in vivo performance of two medium-growing broiler genotypes and on environmental impact. Sixty Kabir Red Plus and sixty New Red chickens were randomly allocated in 20 pens (n = 6 birds per pen). Each pen, i.e., experimental unit, received 1.18 kg dry matter (DM) including soybean (3.39%) in SOY, or pea bean (6.78%) in PEA groups. DM intake, DM refusals and bodyweight (BW) were recorded on pen basis, and average daily gain (ADG) and feed conversion rate (FCR) were calculated. Data on in vivo performance were processed by ANOVA General Linear Model followed by Student−Newman−Keuls post hoc test. Greenhouse gas (GHG) emissions were evaluated on a year basis by GLEAM-i software. The diet did not affect (p > 0.05) DM intake and DM refusals, BW, ADG and FCR. Diet x genotypes affected (p < 0.05) DM intake and DM refusals. PEA diet, cheaper than SOY diet, allowed the reduction in total GHG and CO2, and of meat emission intensity. However, an increase in total CH4 and N2O emissions was observed. The replacement of soybean with pea bean can represent a possible management strategy to reach trade-off between good farming practices and environmental protection on small-scale poultry farms of inner Mediterranean areas.