Abstract In this trial, the effects of early qualitative feed restriction and barrier perch access on some meat quality traits, growth performance, and diet cost analysis of broiler chickens were investigated. A total of 504 1-d-old male chicks (Ross 308) were randomly allocated to four treatments (qualitative feed restriction − QFR; absence-/presence+ and barrier perch − BP; absence-/presence+) with three replicate pens in a completely randomised design involving a 2 × 2 factorial arrangement of treatments. Broiler chickens in the treatment of QFR- were fed with a corn-soybean meal diet containing protein and energy at the level specified in the commercial hybrid catalogue during d 0−42. The treatment of QFR+ was fed with a corn-soybean meal diet containing lower energy (10%) and protein (20%) for the first 21 d, and then between d 22 and 42, they were fed with a diet specified in the commercial hybrid catalogue. In the treatment of BP+, the barrier perch was placed between the feeder and the drinker. Meat quality traits (pH, lightness − L*, redness − a*, yellowness − b*, chroma, hue angle, and cooking loss − CL), growth performance (body weight − BW, body weight gain − BWG, feed intake − FI, and feed conversion ratio − FCR), and diet cost analysis (total diet cost and diet cost per unit weight gain) were recorded. Except for the a* value and hue angle measured at 24-h post-slaughter, the effect of QFR treatments on meat quality traits was insignificant in all measurements. During d 0−42, in the treatments of QFR+, BW, BWG, and FI were lower (P<0.0001, and P=0.005, respectively), and FCR was worse (P=0.014). The QFR treatments did not differ significantly in dietary cost per unit weight gained during d 0−42. As a result, it can be said that early qualitative feed restriction did not significantly affect meat quality traits. The treatment of QFR+ resulted in reduced growth performance. However, diet cost per unit weight gain showed similar values in both QFR treatments (QFR+ €0.75, QFR- €0.76, P=0.511).

An experiment investigated the effects of early qualitative feed restriction and barrier perch provision on the morphometric and biomechanical measurements of the bones in broiler chickens. A total of 504 one-day-old Ross 308 male broiler chickens were randomly assigned to a completely randomized design with a 2x2 factorial arrangement (three replicate pens/group;42 chickens/pen) of qualitative feed restriction (presence-QFR+/absence-QFR-) and the provision of barrier perch (presence-BP+/absence-BP-). On days 21 and 42, morphometric and biomechanical parameters were measured. As a result of this study, barrier perch presence showed no significant impact on morphometric and biomechanical measurements. In the QFR- group, the weight and length of femur bones in 42-day-old broiler chickens were found to be higher (P<0.0001, P=0.034, respectively), alongside increased weight (P=0.001), inner (mediolateral P=0.002 and craniocaudal P=0.040) and outer (mediolateral P=0.047) diameter of the tibiotarsus bones. Furthermore, weight-length index values of the femur and tibiotarsus bones were higher (P=0.001, P<0.0001, respectively) in the QFR- group, while robusticity index values were lower (P=0.029, P=0.006, respectively) on the 42(nd) d y. Regarding biomechanical parameters, the ultimate force level of tibiotarsus bones was statistically higher (P=0.030) at 42 days in the QFR- group. In summary, early protein and energy restriction caused slight decreases in some measurements of the femur and tibiotarsus bones. Strong correlations were observed between specific morphometric and biomechanical parameters, demonstrating their potential to predict biomechanical measurements.

Effects of stocking density (SD) and nano zinc on oxidative status, immune function, and DNA damage in broilers were examined in the current study. Totally 480 one-day-old male broilers (Ross 308) were randomly divided into 4 treatments each contained 8 replicates. A 2 ´ 2 factorial arrangement with two groups for dietary zinc (Zn) form (inorganic or nano) and two groups for SD (low = 12 birds/m2 and high = 18 birds/m2) was conducted. Basal diets based on the corn-soybean meal were formulated. Relative liver weight was lower (P<0.05) in broiler subjected high stocking density (HSD) but other lymphoid organ weights did not affect. Relative lymphoid organ weights were not affected by dietary nano zinc. HSD increased the serum corticosterone level of broiler (P<0.05) but did not affect the blood heterophil:lymphocyte ratio, serum glutathione, superoxide dismutase, and malondialdehyde levels. Dietary nano zinc had no effect on these stress indicators. Serum interferon-gamma, interleukin 12, and interleukin 18 levels were not affected by HSD. Dietary nano zinc tended to reduce the interferon-gamma level (P=0.05) but did not affect interleukin 12, and interleukin 18 levels in broiler. Eeither HSD or nano zinc had no effect on DNA damage in lymphocyte. In conclusion, HSD may decrease the relative lymphoid organ weights and increase the stress indicators but did not affect the immunity and DNA damage. Generally, dietary nano zinc had no effect on stress indicators, immunity, and DNA damage in broiler.

Effects of nano-selenium (nano-Se) and stocking density (SD) on growth performance, carcass yield, meat quality, and feathering score of broilers were investigated in this study. One-day-old 480 broiler chickens (45.32.4 g body weight) (Ross 308) were randomly divided into 4 treatments each comprising of 8 replicates. In the experiment, treatments consisted of a 2  2 factorial arrangement of dietary Se form (inorganic or nano) and SD (low = 12 birds/m2; LSD, and high = 18 birds/m2; HSD). No interaction was noted between Se form and SD for any trait. Nano-Se had no effect on growth performance, however, HSD decreased the body weight gain (BWG) (P0.05) and feed intake (FI) (P0.001) while feed conversion ratio (FCR) was unaffected. Neither nano-Se nor HSD had any effect on the relative carcass, breast, and thigh yields. Nano-Se improved the water-holding capacity (WHC) of breast meat 72-hpost-mortem (P0.05). However, pH, colour, and cooking loss of meat remained unaffected by Se form or SD. There were no differences between nano- or inorganic Se and LSD or HSD regarding feathering scores for back and wing. In conclusion, dietary nano-Se improved the WHC and had no significant effect on other parameters. In addition, HSD may negatively affect the growth performance.

In this study, we evaluated the effect of dietary Zn supplementation on growth performance, serum Zn concentration, litter quality attributes, and occurrence of footpad dermatitis in broiler chickens subjected to chronic heat stress. The study was conducted using a 2 x 2 factorial arrangement of dietary Zn oxide supplementation (0 and 70 mg/kg) and temperature (thermoneutral and chronic heat stress) in a completely randomized design. Five hundred forty-four 1-d-old male broiler chickens were randomly assigned to 4 experimental treatments with 8 replicate pens per treatment having 17 chickens in each replicate pen. Broiler chickens were fed corn-soybean meal-based basal diets for starter (0 to 10 d), grower (10 to 24 d), and finisher (24 to 42 d) growth periods with or without 70 mg/kg supplemental Zn oxide. Growth performance was recorded in terms of body weight gain (BWG), feed intake (FI), and feed conversion ratio (FCR). Serum Zn concentration and occurrence of footpad dermatitis were evaluated at d 14, d 28, and d 42 of experiment. Litter quality attributes were measured at d 1 and d 42 of the experiment except ammonia volatilization that was measured at d 28 and d 42 of the experiment. There was no interaction between dietary Zn and temperature for growth performance, serum Zn concentration, litter quality, and occurrence of FPD. Dietary Zn supplementation had no effect on overall growth performance, serum Zn, and litter quality of broiler chickens. However, supplemental Zn reduced the occurrence of footpad dermatitis in broiler chickens at the end of experiment (P < 0.05). Broiler chickens subjected to heat stress had lower overall BWG (P = 0.002) and FI (P = 0.001). Serum Zn concentrations were similar regardless of the temperature. Chronic heat stress increased the litter pH (P = 0.001), moisture (P < 0.001), temperature (P < 0.001) at d 42, and ammonia volatilization at d 28 (P < 0.001) and d 42 (P < 0.001). Incidence and severity of footpad dermatitis was greater in broiler chickens subjected to chronic heat stress (P < 0.01). Findings of our study indicate that heat stress results in poor growth performance and increases the incidence and severity of footpad dermatitis by lowering the litter quality in broiler chickens. In addition, dietary Zn supplementation may

1. Effects of the incidence of white striping (WS) in relation to carcase weights and yields, breast meat quality and composition, serum biochemistry and oxidant/antioxidant status of breast meat in broiler chickens were investigated. 2. The study consisted of 180, one-d-old male broiler chickens fed maize-soybean meal-based starter, grower, finisher and withdrawal diets identical to commercial chicken diets. On d 49, all the birds were slaughtered and breast fillets were visually scored for the incidence of WS. Breast meat and blood samples were collected and categorised based on the presence or absence of WS. 3. The study revealed greater slaughter weight, carcase and breast fillet weights and yields, lower pH(u) and higher cooking loss of breast meat with WS lesions (P < 0.05). WS-affected breast fillets had greater fat and lower crude protein contents in comparison with normal meat (P < 0.001). Serum creatine kinase levels were greater in broilers with WS (P = 0.011), whereas oxidant/antioxidant status of breast meat remained unaffected. 4. Taken together, the presence of WS on breast muscle altered the quality and nutrient composition of breast fillets and serum creatine kinase levels in broiler chickens fed diets based on maize-soybean meal. Nevertheless, WS was more common in heavier broilers having higher breast weight and yield.

In this study, oxidative stability of liver and breast meat, and immune response were evaluated in broiler chickens fed supplemental phytogenic feed additive (PFA) alone or in combination with Bacillus licheniformis. Three experimental groups - control, PFA (60 mg kg(-1)), and PFA (60 mg kg(-1)) + 0.5 mg kg(-1) B. licheniformis (1.6 x 10(12) cfu g(-1)), each consisting of 5 replicates - were established with 20 one-day-old chickens per replicate (300 birds in total). Growth performance, carcass yield and characteristics, and meat quality remained unaffected. However, supplemental PFA and PFA + B. licheniformis improved the serum biochemistry and jejunal histomorphometry of broiler chickens (P <0.05). PFA and PFA + B. licheniformis groups had lower thiobarbituric acid reacting substances (TBARS) in liver, and freeze-thaw breast meat after 30, 60, and 90 d of storage (P <0.05). PFA and PFA + B. licheniformis supplementation lowered the carbonyl group in fresh and stored breast meat (P <0.05). Antibody titer against infectious bursal disease virus was higher in the PFA + B. licheniformis group than the control group (P <0.05). It can be concluded that PFA or PFA + B. licheniformis in broiler diets improves the health, oxidative stability of liver and breast meat, and immune response of broiler chickens.

In the present study, we examined the effect of nano-selenium (nano-Se) and stocking density (SD) on antioxidant status, immune response, and DNA damage in broiler chickens. A total of 480 one-d-old male broilers (Ross 308) were randomly divided into 4 treatments each including 8 replicates for 42 days. A 2 x 2 factorial arrangement of groups for two dietary selenium forms (inorganic or nano) and two stocking densities [low = 12 birds/m(2) (LSD) and high = 18 birds/m(2) (HSD)] was conducted. Starter, grower, and finisher diets were formulated based on corn-soybean meal according to recommendations of Aviagen. There were no significant differences in the lymphoid organ index due to high stocking density or nano-Se. Neither HSD nor dietary nano-Se had an effect on blood heterophil: lymphocyte ratio, serum corticosterone, glutathione, superoxide dismutase, and malondialdehyde levels. Serum interferon-gamma, interleukin 12, and interleukin 18 levels were not affected either by HSD or by dietary nano-Se. However, an interaction was witnessed between SD and dietary Se form for serum interferon-gamma (P < 0.05). HSD increased the DNA damage in lymphocyte (P < 0.05), but dietary nano-Se had no significant effect on it. In conclusion, HSD and dietary nano-Se may not affect the organ index, stress indicators, and immune function, but dietary nano-Se decreased the possible negative effect of HSD on serum interferon-gamma. HSD increased the DNA damage but dietary nano-Se had no effect.

We investigated the effect of in-feed and/or in-litter supplemental humate against footpad dermatitis (FPD) in broilers fed diets based on barley. Three hundred and sixty 1-day-old Ross 308 broiler chickens were randomly distributed to 24 floor pens (4 treatments, each consisting of 6 replicate pens; 15 chickens per pen) as a completely randomized design with 2 × 2 factorial arrangement of two levels of supplemental humate in feed (0 and 1 g/kg feed) and litter (0 and 5 g/kg litter). Growth performance, intestinal viscosity, litter quality, and incidence and severity of FPD in broilers were measured. In addition, malondialdehyde (MDA) and superoxide dismutase (SOD) levels were determined in blood and footpad tissues of broilers with different FPD scores. The results revealed that there was no interaction between humate supplementation to feed and litter. Neither dietary nor litter supplementation of humate had a significant effect on growth performance, intestinal viscosity, litter quality, and occurrence of FPD. And also, MDA and SOD levels in serum and footpad tissue did not affect by either dietary or litter supplementation of humate. The presence of FPD (score 1) had no effect on MDA and SOD levels in serum, however, increased the MDA and SOD levels (P < 0.001, P = 0.001, respectively) in footpad tissue of broilers. The intestinal viscosity did not differ between FPD scores 0 and 1. In conclusion, findings of this experiment suggest that humate supplementation to feed and litter did not alleviate FPD development in broilers fed diets based on barley. In addition, the presence of FPD lesions increases the MDA and SOD levels in the footpad tissues.

In this study, effect of dietary nano-Zn and stocking density on performance, carcass yield, meat quality, and feathering score of broiler chickens was assessed at 42 d of age. Experimental treatments consisted of a 2 x 2 factorial arrangement of stocking density (low = 12 broiler/m(2) and high = 18 broiler/m2) and dietary Zn form (inorganic or nano). Four hundred eighty 1-d-old male broiler chickens were randomly assigned to 4 treatments with 8 pens in each treatment having 15 chickens per pen. Corn-soybean meal diets were formulated for starter, grower, and finisher phases. The high stocking density (HSD) negatively affected body weight gain (BWG) and feed intake (FI) of broiler chickens at 24 to 42 and 0 to 42 d of experiment (P < 0.05) but did not affect feed conversion ratio (FCR). The BWG (d 10 to 24, d 24 to 42, and d 0 to 42) and FI (d 10 to 24 and d 0 to 42) were negatively affected by dietary nano-Zn whereas, FCR was poor at 10 to 24 d only (P < 0.05). Dietary nano-Zn lowered the BWG at d 24 to 42 (P = 0.028), and FI of LSD and HSD treatments at d 24 to 42 and 0 to 42 (P = 0.019 and P = 0.028, respectively) compared to broiler chickens of LSD group fed inorganic Zn. Neither HSD nor nano-Zn had any effect on the relative yields of carcass, breast, and thigh. Meat quality traits were not affected by either HSD or nano-Zn. There were no differences between groups about back feathering score. However, HSD negatively affected wing feathering score (P < 0.05), and the worst score was observed in HSD dietary inorganic Zn group (P < 0.01). The HSD increased the footpad dermatitis (FPD) scores of chickens at d 24 and 42 (P < 0.01). Dietary nano-Zn reduced the FPD scores on d 24 (P < 0.05) but did not affect FPD on d 42. In conclusion, HSD negatively affected growth performance, wing feathering score, and FPD score in broiler chickens. Dietary nano-Zn suppressed the growth performance of broiler chickens subjected to HSD and did not affect the feathering, however, reduced the FPD score in broiler chickens.

ABSTRACT 1. This experiment determined the effect of increasing mobility in broiler chickens by placing barrier perches between feeders and drinkers. In addition, the limitation of early weight gain by dietary energy and protein dilution on some welfare parameters, tibiotarsus measurements, fear and mobility level was examined. 2. A total of 504 male, one-day-old broiler chickens (Ross 308) were randomly allocated to four treatments with three replicate pens per treatment and 42 broiler chickens per pen as a 2 × 2 factorial arrangement. Treatments included feeding the basal control diet between 0–42 days or a diet diluted by 10% energy and 20% crude protein fed between 0–21 d, with the control diet fed between 22–42 d. The second factor was the presence or absence of barrier perches. All treatments were allocated as a completely randomised design. Welfare parameters (foot pad dermatitis, hock burn, gait score, feather score, breast blister), tibiotarsus measurements (bone mineral content, bone mineral density, fluctuating asymmetry and relative fluctuating asymmetry), tonic immobility and mobility level were recorded. 3. Results showed that access to a barrier perch and the diluted diet increased the mobility in broiler chickens. However, access to a barrier perch had no significant effect on tibiotarsus and welfare parameters. Broiler chickens had better gait scores (P < 0.05) and lower foot pad dermatitis incidence (P < 0.01) in groups fed the diluted diet. The diluted diet had no significant effect on bone mineral density but reduced the tibiotarsus bone mineral content (P < 0.05). 4. In conclusion, the diluted diet provided positive effects in terms of leg health due to weight gain limitations in the early period, thus improving broiler chicken welfare.

A 49-day trial was conducted to determine the impact of dietary amino acid (AA) density and stocking density (SD) on growth performance, carcass traits, meat quality, and white striping (WS) occurrence in broiler chickens. Two hundred eighty-eight Ross 308 male broilers consisting of 6 replicate cages with 8 broilers per replicate were used. Treatments were arranged in a 3 × 2 factorial and consisted of 3 AA densities (normal, 10, or 20% lower than normal) and 2 different SD (high 35 kg/m2 or low 26 kg/m2). Breasts were classified as normal, moderate, and severe for WS. Data were analyzed as a completely randomized design using the GLM procedure. Decreasing AA density decreased overall growth performance, carcass, breast yields, and fillet dimensions linearly, while leg and rib cage yields increased linearly (P < 0.01). High SD decreased hot carcass, breast, wings, and rib cage weights in birds fed normal AA diets (P < 0.05). High SD increased the length of breast fillet (P < 0.05). Cooking loss, breast lightness (L∗), and redness (a∗) at 48 h postmortem increased linearly with decreasing AA density, while ultimate breast pH (pHu) and nitrogen content decreased linearly (P < 0.05). The occurrence of normal, moderate, and severe WS fillets was 45.3, 49.1, and 5.6%, respectively. As the dietary AA density decreased, the occurrence of no WS breast fillets increased linearly, whereas the occurrence of moderate WS fillets and mean WS score decreased linearly (P < 0.05). SD did not affect the occurrence of WS. Severe WS fillets were heavier and had higher cranial thickness, pHu, and fat content and lower yellowness (P < 0.05), but water-holding capacity, nitrogen content, L∗, and a∗ value did not differ among different WS scores. Taken together, WS occurrence and severity increased with higher growth rate. Growth depression created by lowering dietary AA density regardless of SD resulted in a decrease in mean WS score, but it also compromised the growth and meat quality.

Yapılan bu araştırmada, damızlık bıldırcın rasyonlarına gereksinim düzeyini (60 mg/kg) sağlayacak şekilde nano çinko oksit katılmasının (46 mg/kg) yumurta verimi, canlı ağırlık, yumurta kalite özellikleri, sperm kalitesi, kuluçka parametreleri ve karaciğer üzerine olan etkileri incelenmiştir. Çalışmada 20 erkek ve 80 dişi olmak üzere toplam 100 adet bıldırcın (Coturnix coturnix Japonica) kullanılmış, 10 haftalık yaşta olan hayvanlar kontrol ve deneme olmak üzere iki gruba ayrılmış ve her grupta her biri bir erkek dört dişi içeren 10’ar adet alt grup oluşturulmuştur. 10 hafta sürdürülen deneme sonunda, damızlık bıldırcın rasyonlarına nano çinko oksit katılmasının canlı ağırlık, yem tüketimi ve yumurta verimi üzerine herhangi bir etkisinin olmadığı belirlenmiştir. Yumurta kalite özellikleri bakımından ise rasyona nano çinko oksit katılmasının yumurta sarısı rengi üzerinde önemli düzeyde (P<0.001) azalma meydana getirdiği, diğer parametrelerin ise etkilenmediği görülmüştür. Sperm morfolojik bozukluk oranları ele alındığında değerlerin birbirlerine yakın olduğu gözlenmiş, kontrol ve deneme grubunda sırasıyla %32.2 ve 30.0 olarak tespit edilmiştir. Rasyona katılan nano çinkonun döllülük oranı üzerine olumlu etkisinin olduğu (P<0.001), ancak yumurtadan çıkış oranında düşüş (P<0.05) meydana getirdiği ve erken embriyonik ölüm oranını artırdığı (P<0.05) tespit edilmiştir. Karaciğer dokusunda yapılan histopatolojik değerlendirmede nano çinko oksit katılan grupta karaciğerde şiddetli düzeyde yağlanma meydana geldiği belirlenmiştir. Sonuç olarak; önerilen düzeyde nano çinko oksit katılmasının performans üzerine etkisinin olmadığı, sarı rengi, çıkım ve erken embriyonik ölüm oranı ile karaciğer üzerine olumsuz etkilerinin olduğu ortaya konmuştur.

Bu çalışma damızlık bıldırcın rasyonlarında nano selenyum (Se) kullanılmasının verim, canlı ağırlık artışı, yumurta kalite özellikleri, sperm kalitesi, kuluçka parametreleri ve karaciğer üzerine etkilerini belirlemek amacıyla yapılmıştır. Araştırmada 20 erkek ve 60 dişi olmak üzere toplam 80 adet 10 haftalık yaşta bıldırcın (Coturnix coturnix Japonica) kullanılmıştır. Hayvanlar kontrol (K - inorganik sodyum selenit) ve deneme (D - nano sodyum selenit) olmak üzere iki gruba ayrılmış, her grup altında da her biri bir (1) erkek üç (3) dişi içeren 10 adet alt grup oluşturulmuştur. Nano Se kullanılması verim, canlı ağırlık ve yem tüketimi üzerine herhangi bir önemli etki oluşturmamıştır. Ancak yumurta ağırlığı (P<0.01) ve sarı rengini (P<0,05) azaltırken, kabuk ağırlığı (P<0.001), Haugh birimi ve kabuk indeksini (P<0.01) artırdığı görülmüştür. Kabuk kalınlığında ise herhangi bir önemli etki belirlenmemiştir. Nano Se kullanımı spermatozoalarda başa bağlı bozukluk oranını artırmış (P<0.05) ancak diğer morfolojik parametreleri etkilememiştir. Nano Se döllülük oranı ve kuluçka randımanını önemli düzeyde (P<0.05) düşürmüş, diğer kuluçka parametrelerini ise etkilememiştir. Histopatolojik olarak deneme grubundaki karaciğerlerde yağ vakuolleri olduğu belirlenmiştir. Sonuç olarak, rasyonlarda 0.2 mg/kg nano Se’nin kullanılması genel olarak olumsuz bir etki oluşturmuştur. Bu nedenle daha düşük düzeylerde kullanılması önerilebilir.

ABSTRACT The present study was conducted to investigate the influence of different levels of dietary phytogenic feed additive (PFA) on growth performance, caecal microbiota, and intestinal morphology of broilers. A total of 480 Ross-308 one-day-old male broilers chicks (body weight 43±3 g) were randomly assigned to 32 replicate pens of four experimental groups, each experimental group consisting of 8 replicates (each replicate pen consisting of 15 chicks). A basal diet was formulated based on corn and soybean meal that was fed to the control group. Other dietary treatments received a commercial PFA at 100 mg/kg (PFA100), 125 mg/kg (PFA125), and 150 mg/kg (PFA150). Body weight gain, feed intake, and feed conversion rate of broilers were recorded on 1-21, 22-42, and 1-42 days of age. One bird was slaughtered on the 21st and 42nd days and caecal contents were aseptically collected. Jejunal tissue samples were also collected on the same days. Total aerobic bacteria, coliforms, Escherichia coli, and lactobacilli were counted in the caecal contents. Villus height, villus diameter, crypt depth, muscular thickness, and goblet cell number per villus were recorded. There was no difference among the dietary treatments for growth performance and caecal microbe populations at any phase. However, the dietary PFA supplementation increased the villus height, villus width, muscularis thickness, and reduced the crypt depth and goblet cell number per villus in broilers compared to those fed control diets. In conclusion, this study suggests that dietary supplementation of a PFA consisting of blend of different spices and essential oils did not improve growth performance and caecal microbial populations despite a positive improvement in the jejunal morphometry of broilers.

The present study was conducted to evaluate the protective effect of dietary boric acid supplementation on the development of incidence and severity of footpad dermatitis (FPD) in broiler chickens subjected to normal or high stocking densities (NSD or HSD). A total of 576 1-day-old ROSS 308 broiler chickens were randomly allocated to 4 treatments (8 replicate pens per treatment) in a 2 × 2 factorial arrangement of dietary boric acid (0 and 60 mg/kg) and stocking density (NSD 14 birds/m2 and HSD 22 birds/m2). Basal diets were formulated for starter, grower, and finisher phases. Growth performance, litter quality (litter pH, moisture, temperature, and NH3 volatilization), serum and litter boron levels, and incidence and severity of FPD were recorded. The HSD affected the body weight gain and feed intake of broiler chickens during all phases and 0 to 42 (P < 0.05), whereas feed conversion ratio (FCR) was poor at 0 to 21 days only. Dietary boric acid had no effect on the growth performance of broiler chickens. Litter pH, moisture, and NH3 volatilization were higher in broiler chickens subjected to HSD (P < 0.05). Thus, the incidence and severity of FPD increased in response to HSD (P < 0.05). Dietary boric acid reduced the litter pH and NH3 volatilization on day 42 of experiment (P < 0.05). However, dietary boric acid supplementation had no effect on the incidence and severity of FPD. Boric acid supplementation in broiler diets increased the serum and litter boron levels at day 42 in broiler chickens subjected to NSD or HSD (P < 0.05). In conclusion, HSD resulted in poor growth performance, litter quality, and greater incidence and severity of FPD in broiler chickens. Dietary boric acid was ineffective against FPD in broiler chickens although it improved the litter quality by lowering the litter pH and NH3 volatilization.

A trial was conducted to investigate the effect of dietary prebiotics supplementation on growth performance, relative carcass and organ weight, gut microbiome, and blood malondialdehyde (MDA) in broiler chickens subjected to delayed feed and water access post-hatch. A total of 648 one-d-old chicks (Ross 308) were randomly divided into 6 experimental groups, each consisting of 6 replicate pens having 18 chicks in each pen. The study followed a completely randomised design with 3x2 factorial arrangement of three levels of post-hatch restriction time (0, 24, and 48 h) and basal diets with or without mannan oligosaccharide (MOS) prebiotics supplementation (0 and 0.1% for starter and grower or 0 and 0.05% for finisher). The trial lasted for 42 days. The chicks were weighed at the end of restriction periods. Body weight gain (BWG), feed intake, and feed conversion ratio (FCR) were recorded for days 1 -21, 22-42, and 1-42. Relative carcass and organ weights were recorded on day 42 after slaughter. Gut microbe populations (mesophiles, coliforms, lactobacilli, and Enterobacteriaceae spp.) were enumerated on days 6 and 15 of the experiment. Blood MDA levels were measured at the end of the restriction period on days 15 and 42. There was no interaction between prebiotics and restriction on any mentioned parameters. Prebiotics had no effect on BWG, feed intake, FCR, relative yields of carcass and organs, gut microbial populations, or blood MDA levels. BWG of broilers subjected to 48 h restriction was lower (P < 0.05) for days 1-21 compared to those subjected to 0 and 24 h. Feed and water restriction for 48 h post-hatch increased the feed intake (on days 22-42 and 1-42) and FCR (at days 1 -21, 22-42, and 1-42) in comparison with those restricted for 0 and 24 h post-hatch (P < 0.01 and P < 0.001, respectively). There was no effect of restriction on relative carcass and organ yields, and blood MDA. On day 6 of the experiment the count of mesophiles was higher in broilers restricted for 48 h (P < 0.001) and coliforms and Enterobacteriaceae spp. counts were higher in broilers subjected to 24 h restriction compared to 0 or 48 h (P < 0.01 and P < 0.001, respectively). In conclusion, the use of prebiotics in broilers with post-hatch feed and water restriction did not influence growth performance, relative carcass and organ weight, gut microbe populations, and blood MDA level. However, post-hatch feed restriction for 48 h may negatively affect growth performance.

A study was conducted to evaluate the effect of dietary tannic acid and barley supplementation on growth performance, intestinal viscosity, litter quality, and footpad dermatitis (FPD) in broiler chickens. Five hundred forty-four 1-d-old male broiler chicks were randomly assigned to dietary treatments with 8 replicated pens per treatment and 17 broiler chickens pen as a 2 × 2 factorial arrangement of 2 diets (a corn-soybean meal diet or a diet with 30% barley) and tannic acid (0 and 2g/kg) in a completely randomized design. Growth performance, intestinal viscosity, litter quality, and FPD incidence and severity were recorded. The results showed that there was no interaction between diets and tannic acid levels. Barley-based diets reduced (P < 0.05) the body weight (BW) gain at 0–42 d, and feed intake at 21–42 d and 0–42 d. At 28 d of experiment, the viscosity of intestinal contents of anterior and posterior segments was greater (P < 0.05) in broiler chickens fed diets with barley. Similarly, the viscosity of intestinal contents of posterior segment was greater (P < 0.05) at 42 d, in broiler chickens fed barley-based diets. Litter pH, moisture, and NH3 volatilization were increased (P < 0.05) in response to barley-based diets. Barley-based diets increased (P < 0.05) the incidence and severity of FPD lesions in broiler chickens at 14, 28, and 42 d of experiment. Although dietary tannic acid had no effect on performance, intestinal viscosity, and litter quality compared to those fed diets without tannic acid (P > 0.05), it tended to reduce body weight gain (P = 0.05) and increase feed conversion ratio (FCR; P = 0.09) at 0–21 d and NH3 volatilization on 28 (P = 0.08) and 42 d (P = 0.07). Dietary tannic acid supplementation prevented the FPD lesion development and reduced (P < 0.05) the total FPD lesions at d 42. Moreover, the severe lesions decreased (P = 0.08) on d 42 in broiler chickens fed tannic acid. In conclusion, barley-based diets may worsen the growth performance and litter quality, and increase the intestinal viscosity that increases the incidence and severity of FPD in broiler chickens. Dietary tannic acid supplementation may not affect the growth performance, intestinal viscosity, and litter quality. However, it may reduce the incidence and severity of FPD in broiler chickens.