Linking key husbandry factors to the intrinsic quality of broiler meat

Broiler farming is the fastest-growing animal production sector and broiler meat is the second most-consumed meat in the world. The intensification of broiler production often has a negative impact on the meat quality and carcass characteristics. Consumers, however, expect a quality product from animals reared extensively on farms providing good animal welfare, often intuitively associated with extensive farming practices. Therefore, this literature review investigates how the critical factors contributing to the degree of extensiveness of broiler production affect the quality of meat. We used the data from scientific articles published in the years 2012-2021 to analyze the effect of diet (n = 409), genetics (n = 86), enrichment (n = 25), and stocking density (n = 20) on meat quality and carcass characteristics. Minerals and microelements supplementation in the diet improved all the meat quality aspects: sensory, physical, and chemical in most studies. Minerals and enzymes in the diet had beneficial effects on carcass characteristics, unlike feed restriction and ingredient substitutions. The impact of outdoor access on meat quality and carcass characteristics was most frequently examined, in contrast to the use of perches or effects of litter quality. Overall, enrichment did not affect the meat's sensory or physical parameters, but outdoor access improved its lipid composition. Lower stocking density deteriorated intramuscular fat content, decreased tenderness and juiciness, yet lowered cooking and drip loss, and increased carcass and breast muscle yields. When it comes to genetics, in general, slow growing broiler strains have better meat quality parameters, especially regarding yellowness (b*), redness (a*), cooking and drip loss. Our review shows that the factors which contribute to extensiveness of broiler production systems and birds' welfare also affect meat quality and the carcass characteristics.

Expression of nutrient transporter genes in response to dietary rice gluten meal and protease enzyme supplementation and the consequent effects on growth, nutrient digestibility, immunity and jejunum histomorphometry in chicken

The objective of this study was to investigate the effects of feeding rice gluten meal (RGM) as an alternative protein source along with protease enzyme supplementation on growth performance, expression of nutrient transporter genes, nutrient digestibility, immune response and gut histomorphometry of broiler chicken. Proximate analysis of RGM revealed 923 g dry matter (DM), 500 g crude protein (CP), 69.2 g ether extract, 94.7 g crude fiber, 215.4 g nitrogen-free extract, 43.7 g ash, 6.20 g calcium, 7.80 g total phosphorus, 18.99 MJ gross energy and 12.68 MJ metabolizable energy per kg diet. Significant upregulation of nutrient transporter genes (PepT1, EAAT3 and mucin) and better growth performance was observed in the birds fed control diet which was statistically similar to the birds fed 150 g RGM compared to birds fed higher RGM levels. Histomorphometry of jejunum, nutrient digestibility, and immune response of birds did not reveal any significant effect of RGM or protease enzyme supplementation. However, the inclusion of RGM up to 150 g/kg diet resulted in significant decline of feed cost/kg live weight gain, dressed meat yield and eviscerated meat yield by 13.13%, 12.99% and 13.36%, respectively compared to control. Thus, it was concluded that the inclusion of 150 g RGM/kg diet in broiler chicken ration has no adverse effects on the growth pattern of birds and can be used for least-cost feed formulation for chicken.

Effects of replacing soybean meal with linseed meal in broiler diet on selected broilers’ blood parameters, meat chemical composition, fatty acid profiles, and sensory characteristics

The study was conducted with the objective of determining the effects of the dietary replacement of soybean meal with graded levels of linseed meal on selected blood parameters, meat composition, fatty acid profiles, and meat quality of broiler chickens. Cobb500 broilers were fed diets containing linseed meal at 0% (T1), 6.5% (T2), 13% (T3), 19.5 (T4), and 26% (T5), replacing 0% to 100% soybean meal in compound rations for 45 days. The experiment was conducted using a completely randomized design with five treatments, each replicated three times with 12 birds. Blood hematological indices were not affected (P>0.05) by treatment diets while among the blood biochemistry triglyceride and cholesterol concentrations in T1 were higher (P<0.05) than in T3, T4, and T5. Glucose was higher in T3, T4, and T5 than in T1 and T2 (P<0.01). The breast and thigh proximate composition for crude protein (CP), ether extract (EE), ash, carbohydrate, and gross energy were similar (P>0.05) among treatments. The sensory scores for breast and thigh meat samples were not different (P>0.05) among treatments. The palmitic acid content of breast and thigh meat was higher (P<0.05) in T1 and T2 than in the other treatments. Eliadic and stearic acid concentrations in thigh meat were greater (P<0.05) in T1, T2, and T3 than in T4 and T5. The oleic and linoleic acid contents of thigh meat were higher (P<0.05) in T2 and T3 than in the rest of the treatments. Breast linolenic acid was high (P<0.05) in T5 but similar in thigh meat. Total saturated fatty acid (SFA) showed a decreasing trend with an increasing level of linseed meal (LSM) in the ration. The ratio of monounsaturated fatty acid (MUFA) to SFA for breast and thigh was higher in T4 and T5 than in T1 and T2. Breast meat ratio of omega-6 (n-6) to omega-3 (n-3) showed a decreasing trend as the level of LSM replacement for soybean meal (SBM) in the ration increased. Generally, linseed meal replacement levels up to 26% in the broilers’ diet improves the essential fatty acid content of chicken meat without affecting the proximate composition and the chickens’ normal blood indices and does not alter meat sensory attributes.

Effect of Dietary Enrichment with Flaxseed, Vitamin E and Selenium, and of Market Class on the Broiler Breast Meat-Part 2: Technological and Sensorial Traits

The influence of diet enrichment with flaxseed, selenium and vitamin E, and market class on breast meat was investigated in terms of technological and sensorial quality of breast meat. A randomized complete block design with an experimental unit of n = 6000 broilers receiving a standard or enriched diet, and slaughtered at 37 (light class), 47 (medium class), or 57 (heavy class) days of life, was developed. Then, enriched and standard breast muscles from every market class were studied for their technological and sensorial traits—both at 24 h post-mortem and after one month of frozen storage—by a statistical multiple linear model. Redness and yellowness of muscles significantly (p < 0.05) increased and decreased with increasing market age. Moreover, the yellowness significantly (p < 0.05) raised after frozen storage. However, obtained data were always indicative of a normal meat color. The water holding capacity improved following fed enrichment and significantly (p < 0.05) worsened after frozen storage. For the sensory analysis, juiciness and chewing rest of meat resulted significantly (p < 0.05) improved with increasing slaughtering age and diet enrichment, as well as their mutual interaction, while they deteriorated after frozen storage. Overall, fresh and enriched muscles from heavy broilers had the best technological and sensorial traits, thus, confirming that market size and diet should be highly considered to obtain breast meat with greater consumer acceptance.

Evaluation of energy and amino acids of brown rice and its effects on laying performance and egg quality of layers

Two experiments were conducted to determine apparent metabolizable energy (AME), nitrogen-corrected AME (AMEn), and ileal digestible amino acid (AA) content of brown rice (BR) and to investigate the effect of dietary supplementation of BR on laying performance and egg quality of laying hens. In Exp. 1, 72 Hy-line Brown layers (49-week-old) were allocated to two treatments using a completely randomized block design, and each treatment included six cages per treatment and six hens per cage. A semi-purified diet was formulated to include BR as the sole source of AA and energy and an N-free diet was used to determine basal endogenous loss of AA. The hens were fed a commercial layer diet for adaptation to the experimental environment and diet for 7 days from d 0, and then fed experimental diets for 5 days from d 7. Excreta were collected from d 10 to 11 and ileal digesta were collected on d 12. On a dry matter (DM) basis, the AME and AMEn of BR was determined at 3,773 and 3,729 kcal/kg, respectively. The apparent ileal digestibility (AID) of BR ranged from 32.7% for Thr to 73.7% for Arg. The range of the standardized ileal digestibility (SID) value was between 79.4% for Met and 96.6% for Lys. In Exp. 2, 252 Hy-line Brown layers (44-week-old) were divided into four groups, comprising seven replicates of nine birds each and assigned to four experimental diets containing 0 (Control), 5%, 10%, or 15% BR for 5 weeks. The BR-containing diets were formulated to be equal in the content of AMEn and digestible AA to those of the diet without BR. No significant differences were observed in laying performances. Egg quality and blood profiles were not linearly or quadratically affected by dietary treatments. These results suggest that up to 15% BR can be included into layer feed without any adverse effects on laying performance and egg quality, if its energy and digestible AA values are well evaluated.

Effect of Fungal Solid-State Fermented Product in Broiler Chicken Nutrition on Quality and Safety of Produced Breast Meat

The aim of this work was to analyse the effect of addition of 10% (w/w) fermented bioproduct into commercial broiler feed on fatty acid profile, lipid oxidative stability, and sensory properties of chicken breast meat. The fermented bioproduct was prepared by fermentation of cornmeal by filamentous fungi Umbelopsis isabellina CCF 2412 in solid-state fermentation (SSF) process and the final bioproduct was enriched with gamma-linolenic acid and beta-carotene. In the experiment, 80 pieces of 1-day-old chickens COBB 500 were used. Half of them (control group) were fed only with commercial feed. Chickens of the experimental group were fed with commercial feed, and, from the 11th day of age until the time of slaughter (39th day), 10% of commercial feed was replaced with fermented bioproduct. Application of fermented bioproduct into commercial feed mixture positively influenced profile of fatty acids in breast meat. The amount of gamma-linolenic, alpha-linolenic, and oleic acids in fat of breast muscles was increased and n-6/n-3 ratio was significantly decreased. Profile and content of PUFAs did not change after thermal treatment of meat. Oxidative stability of fat and sensory properties of the meat during the storage (4°C, 7 days) of meat were not affected by fermented bioproduct.