The challenge of identifying alternatives to subtherapeutic levels of antibiotic growth promoters (AGP) in animal feed has led to increased interest in feed additives such as exogenous enzymes and direct-fed microbials (DFM). Six corn soy-based dietary treatments were designed to investigate the effect of high-efficiency xylanase alone, Bacillus spp. probiotics alone, and their combination vs. a commonly used antibiotic growth promoter (bacitracin methylene disalicylate; BMD) on live performance and environmental Clostridium perfringens load of broiler chickens with eight replicate pens per treatment. Diets were as follows: standard diet (positive control; PC); 130 kcal/kg reduced-energy diet (negative control; NC); NC with xylanase (NC + Xy); NC with probiotics (NC + Pro); NC with xylanase and probiotics mix (NC + XyPro); and NC with BMD (NC + BMD). Data were analyzed as one-way ANOVA. At 35 and 42 days, birds fed with NC + XyPro and NC + BMD were heavier (P < 0.05) than birds fed with NC. Improvement in feed conversion ratio (FCR) (P = 0.0001) was observed from 1 to 42 days by ~3 points in both NC + XyPro and NC + BMD compared to NC. The NC + XyPro reduced lesion scores by 66% compared to PC and NC. Litter C. perfringens cell count was reduced by ~16% with supplementation of XyPro or BMD. It can be concluded that a blend of xylanase (10 XU/g feed) and Bacillus spp. [1 × 10⁵ colony forming units (CFU)/g feed] can be used as an alternative to AGP in low-energy broiler diets.

The increased demand for poultry meat and the shift toward portioned and further processed products has been accompanied by genetic improvement and progress in nutrition and management to increase growth rates and improve feed efficiency. Animal protein continues to be the most demanded and expensive protein source worldwide. Poultry is an animal protein commonly accepted among different faith groups and relatively more affordable than other animal protein sources. In addition, poultry meat has lower fat, cholesterol, and sodium content compared to red meat. This review aims at summarizing the available information about skeletal muscle structure, conversion of muscle to meat and how it affects poultry meat quality, the different myopathies historically been identified and other emerging myopathies, then discussing how meat quality affects consumer perception and consumption trends, and finally discussing few of the proposed solutions to overcome the issues of decreased meat quality, including nutritional strategies.

Two 49 d floor pen studies were conducted to evaluate the effects of litter type and dietary coarse ground corn (CC) inclusion on broiler live performance, gastrointestinal tract (GIT) development, and litter characteristics. Experiment 1 was a 2 × 2 factorial arrangement of 2 genders (male or female) and 2 CC levels (0 or 50%). From 15 to 35 d, the addition of CC decreased feed intake (P < 0.01) and BW gain (P < 0.05) of males but not females. The inclusion of CC decreased feed intake (P < 0.01) and BW gain (P < 0.01) from 0 to 49 d but improved adjusted feed conversion ratio (AdjFCR) from 35 to 49 d (P < 0.05). Male broilers exhibited better live performance than females during the study as evidenced by greater feed intake (P < 0.01) and BW gain (P < 0.01), and improved FCR (P < 0.01), but with increased mortality (P < 0.05). The inclusion of CC increased relative gizzard weight (P < 0.01) and decreased relative proventriculus weight (P < 0.01) at 49 d. Experiment 2 was a 2 × 2 factorial arrangement of 2 CC levels (0 or 50%) and 2 litter types (ground old litter or new wood shavings litter). The inclusion of CC decreased feed intake throughout the experiment without affecting final BW when only males were used and improved FCR after 25 d (P < 0.01). New litter improved FCR from 1 to 14 d (P < 0.01). At 49 d, the birds fed the CC diet had reduced excreta nitrogen (P < 0.05) and litter moisture (P < 0.05). In conclusion, 50% CC inclusion initially produced negative effects on live performance that became positive as BW increased. The effects of CC became evident at an earlier age for males. New litter had only a marginal benefit on broiler live performance.

Xylanase enzymes and other feed additives are being used more commonly in poultry feed to reduce feed cost, improve performance, and maintain gut health. Five corn-soy-based dietary treatments were designed to compare the effect of different inclusion levels of high-efficiency GH11 xylanase on live performance, gut lesions, and Clostridium perfringens excretion in littler samples of broiler chickens. Diets were the standard diet (positive control; PC); a diet of reduced energy by 130 kcal/kg diet (negative control; NC); NC with xylanase at 10 XU/g of feed (NC + 10); NC with xylanase at 12.5 XU/g of feed (NC + 12.5); NC with xylanase at 15 XU/g of feed (NC + 15). Data were analyzed with one-way ANOVA. At 42 d, birds fed NC + 12.5 and NC + 15 were heavier (P < 0.05) than NC and comparable improvement to birds fed PC. Significant Improvement in FCR (P = 0.0001) was observed from 1 to 42 d for NC + 12.5 and NC + 15 compared with NC. Supplementation of xylanase reduced (P < 0.005) 21 d intestinal lesion score at 21 d with further improvement (P < 0.0001) at 42 d. NC + 15 reduced lesion scores by 24% compared with NC. Xylanase supplementations reduced litter C. perfringens cell forming unit per gram (CFU/g) compared with NC with the highest reduction of NC + 15 treatment by ~27%. In conclusion, xylanase can be included in reduced-energy diets up to 15 XU/g of feed to improve live performance, energy digestibility, and reduce intestinal lesion scores in broilers.

This study was conducted to investigate the effect of graded levels of β-mannanase supplementation in broiler diets on growth performance, energy digestibility, and lesion scores in d-old birds fed mash, corn-soybean meal-based diets and raised to 42 d. Five dietary treatments were investigated: 1) positive control diet (PC) containing standard energy; 2) negative control (NC) with 100 kcal/kg diet reduction in AME compared to PC; 3) NC supplemented with 30 U/g β-mannanase (NC + 30 U); 4) NC supplemented with 60 U/g β-mannanase (NC + 60 U); and 5) NC supplemented with 90 U/g β-mannanase (NC + 90 U). Each treatment had 6 replicate pens with 52 chicks per replicate. Data was analyzed using 1-way ANOVA, and means were separated by LSMEANS. Reduction of 100 kcal/kg feed (NC) resulted in an overall body weight gain reduction of 51 g (P < 0.05) and feed conversion loss of approximately 4 points (P < 0.05) compared to PC at 42 d of age. At the same time, supplementing β-mannanase at 60 and 90 U/g improved growth performance parameters compared to NC, while 30 U/g did not result in significant improvements beyond NC; body weight gain was improved (P < 0.05) by 87, and 106 g when β-mannanase was supplemented at 60 and 90 U/g, respectively, compared to NC. This corresponded to an improvement by 6 and 7 points in feed conversion for 60 and 90 U/g supplementation, respectively, compared to NC. Furthermore, AMEn was improved (P < 0.05) by 15, 97, and 116 kcal/kg at 42 d when β-mannanase was added to NC at 30, 60, and 90 U/g, respectively. Digesta viscosity measured at 42 d was decreased (P < 0.05) by β-mannanase supplementation of 60 and 90 U/g, compared to NC, while 42 d lesion scores were improved (P < 0.05) by β-mannanase supplementation compared to NC. Data demonstrated that dietary supplementation of β-mannanase improved growth performance, energy digestibility, and reduced viscosity and lesion scores when supplemented with diets with a reduced energy content of 100 kcal/kg compared to a standard energy diet.

The present study aimed to assess the effect of dietary betaine (B) and/or creatine (C) on performance and thermoregulatory responses of broiler chicks. Indian River broiler chicks, fitted with compact thermosensors, were reared to market age (five weeks). The chicks were randomly distributed into four treatment groups, in a 2 × 2 factorial arrangement of treatments—basal control diet (Control group: CONT; B−/C−); 1 g betaine/kg feed (Betaine group: BETA; B+/C−), 1.2 g creatine monohydrate/kg feed (Creatine group: CRET; B−/C+), and combination (Betaine and Creatine group: COMB; B+/C+) of both supplements. At 31 days of age, 20 chicks from each group were exposed to acute heat stress (A-HS) for 3 h (34.45 ± 0.20 °C), and hemogramic profiles were screened before and after. Performance parameters (feed intake, body weight gain, and feed conversion ratio) were reported on a weekly basis, and carcass meat quality was evaluated at the end of experiment. Redness of breast was higher due to B and C treatments separately than the CONT group (B by C interaction; p < 0.05). Compared to the CONT, dietary supplements alleviated hyperthermia responses, with B alone being more efficient than C or COMB treatments. The mitigation of hyperthermia is likely mediated by enhancement of water balance indicators. Although not efficient in improving growth performance, dietary B and/or C are efficient in improving thermophysiological performance and survival of finishing broiler chicks under A-HS.