This study evaluated the effect of intra-amniotic synbiotic inclusion and continued synbiotic supplementation in the diet on the performance, intestinal epithelium integrity, and cecal microflora of broiler chickens. In Experiment 1, 510 eggs containing viable embryos were divided into 3 groups of 170 eggs each. The first group was not injected and served as a negative control ( NC: ). The next group was injected with 0.9% NaCl and was the positive control ( PC: ). The synbiotic-injected group ( S: ) was injected with a 0.5% inulin and 1 × 10 Enterococcus faecium solution. The non-injected and synbiotic injected groups were further divided into 2 sets for Experiment 2 and the birds were offered either a basal or synbiotic supplemented diet (1% inulin and 2 × 10 E. faecium cfu/kg feed). One hundred ninety-six broiler hatchlings were randomly allocated in a 2 × 2 factorial arrangement that included an intra-amniotic treatment (non-injected or synbiotic injected) and a dietary treatment (basal or synbiotic supplemented diet). The results showed that the administration of an intra-amniotic synbiotic to embryonated eggs on d 17 of incubation did not affect the hatchability or hatching weight of the birds. However, intra-amniotic synbiotic inclusion had a positive effect on FCR at d 0 to 42 (P = 0.041) and d 22 to 42 (P = 0.036). There was no significant interaction effect on the growth performance of the birds between the intra-amniotic and dietary synbiotic treatment during different or entire experimental periods. Villus height and goblet and proliferating cell nuclear antigen ( PCNA: ) positive cell counts were positively influenced by intra-amniotic and dietary synbiotic treatments. Our results also indicated that intra-amniotic synbiotic injection followed by dietary supplementation with a synbiotic significantly increased Lactobacillus colonization and decreased coliform population in the broiler cecum. Cecal butyric acid concentration increased proportionally to the cecal Lactobacillus count with dietary synbiotic supplementation on d 42. In summary, combined intra-amniotic and dietary synbiotic treatments improved broiler intestinal integrity and increased cecal beneficial bacteria populations.

The purpose of this study was to assess the effects of dietary fish oil (FO) and rooibos supplementation on semen quality, fatty acids composition and reproductive performance of aged male broiler breeders. Seventy‐two 47‐week‐old Ross broiler breeder roosters were randomly assigned to a 2 × 3 factorial arrangements to include two FO concentrations (0% and 2%) and 3 rooibos concentrations (0%, 1.5% and 3%) for 13 weeks consecutive. The different diets affected semen parameters significantly (p < 0.05), except for the semen concentration and abnormality of the sperm. The sperm of the FO and 3% rooibos‐treated group showed better motility and viability when compared to the other groups (p < 0.05). The susceptibility of semen to lipid peroxidation was increased in roosters fed the rooibos‐free diets (p < 0.05), but it was reduced (p < 0.05) when the diet was supplemented with 1.5% and 3% rooibos. In addition, at 64 weeks, the highest concentration of testosterone was observed in the roosters fed a diet that included 2% FO and 3% rooibos (p < 0.05); however, the difference in testosterone levels between Week 52 and Week 64 was not significant (p > 0.05). The fertility rate of collected eggs from the FO and 3% rooibos group was higher (p < 0.05) than that of the other groups at the end of the experiment. In conclusion, dietary inclusion of FO along with rooibos improved seminal quality and reproduction performance in aged roosters.

White striping (WS), characterized by white striations on the Pectoralis major muscle, is an emerging problem for the broiler industry. Thus, the impact of WS on meat quality has become a current research topic. In this context, a 2‐year follow‐up study, to reveal the prevalence of WS in broiler integrations, was undertaken. Additionally, a laboratory experiment was conducted to determine the oxidative quality during storage and the differences in proximate composition, colour and fatty acid and amino acid profiles of broiler breast fillets scored visually as normal, moderate and severe. In integrations, the WS incidence increased with increasing broiler age and more than 50% of breast fillets obtained from 32‐ to 35‐day‐old broilers and 36‐ to 39‐day‐old broilers had stripes with different scores. Lower protein and higher fat contents were measured in the moderate and severe scored fillets than the normal fillets (p < 0.001). Severe score stripes induced the formation of less redness on the ventral surface (p < 0.05) and a darker colour on the dorsal surface (p < 0.01). The lowest histidine, arginine and tryptophan amounts were determined in severe fillets (p < 0.05). Moderate and severe scored fillets were rich in polyunsaturated fatty acids implying that they were sensitive to lipid oxidation. That suggestion was further proven by the higher TBARS values. Freeze‐thawing induced the formation of carbonyl compounds, but it did not cause differences in sulphydryl groups. Briefly, we suggest that different WS scores may affect the physicochemical and oxidative quality of breast fillets; however, more studies are needed to assert an accurate and explicit judgement.

Energy, known as the most expensive nutrient in broiler feed, is what strongly adjusts and affects the growth of broilers. Creatine has a key role in cellular energy metabolism and could be synthesised from guanidinoacetic acid (GAA) in the liver; however, its de novo synthesis is not able to adequately fulfil the demand of energy metabolism, especially in fast-growing modern broilers. So the aim of the study was to evaluate the efficiency of commercial GAA in energy-reduced broiler diets on performance and intestinal development. Overall, 11 400 day-old Ross 308 chicks were randomly allocated to six dietary treatments with ten replicates in each. Dietary treatments were designed as a 3 × 2 factorial arrangement with three levels of dietary metabolisable energy (AME_n)  recommended by Aviagen for Ross 308 broilers (12.55 MJ/kg, 12.97 MJ/kg and 13.38 MJ/kg for starter, grower and finisher, respectively), 0.209 MJ/kg and 0.418 MJ/kg reduced and two levels of GAA (0.00% and 0.06%). There was no significant GAA × AME_n interaction for all performance parameters, carcass traits and jejunal morphological parameters (except for the villus width). Reduction of dietary AME_n (0.209 MJ/kg and/or 0.418 MJ/kg) caused a significant depression in body weight (BW) gain (P &lt; 0.001) and feed conversion ratio (FCR) (P &lt; 0.001). However, a decreasing AME_n level increased villus height (P &lt; 0.003) and villus surface area (P &lt; 0.03), while crypt depth and villus width were similar. The GAA improved final BW and FCR by 1.77% and 1.66%, respectively (P &lt; 0.001). Birds fed low energy diets supplemented with GAA showed a significant improvement in the performance so that BW and FCR were the same as in the control birds; however, no such positive effects were obtained in jejunal villus development. Hence, it might be concluded that 0.06% GAA supplementation improves BW and FCR and can save at least 0.209 MJ/kg dietary AME_n in broiler diets.

The current study was carried out to evaluate the response of broiler chicks to dietary energy. In total 11,400 day‐old Ross‐308 chicks (95 males and 95 females per pen) were placed in the study for 42 days. Hatchlings were randomly distributed to 6 dietary treatments with 10 replicates. Aviagen metabolisable energy (ME) recommendation for Ross 308 was served as a positive control (PC) and other treatments were adjusted to 101.25, 98.75, 97.50, 96.25 and 95% of PC. Birds had free access to water and pellet feed. Body weight (BW), Feed intake, feed conversion ratio (FCR), carcass yield and jejunal morphometric analysis were determined per replicate. Feeding the birds with 1.25% higher ME than PC did not result in any improvement in BW, FCR, mortality and carcass parameters. Significant linear improvement was observed at starter period for BW and FCR with the reduction of dietary ME (p < 0.05). There was no significant impairment in final BW with the reduction of ME up to 5.0%. Whole period FCR reduced by 0.009, 0.022, 0.014, 0.037 points by lowering ME by 1.25, 2.5, 3.75 and 5%, respectively (linear, p < 0.05). Carcass yield, abdominal fat and pancreas weights were not significantly influenced (p > 0.05). However, significant improvement in villus height, surface area (quadratic and cubic, p < 0.05), and villus width (quadratic, p < 0.05) were observed with 2.5 and 3.75% reduction of dietary ME. Dietary treatments had no significant effect on liver haemorrhagic lesion score. The results of the current research suggest that the optimum level of dietary energy level of modern broilers may be lower than the one recommended by the primary breeders. Lowering dietary energy density up to 5% leads to 0.03 points reduction in FCR without any negative effect on BW.