Excessive phosphorus excretion by intensive livestock operations is a growing concern worldwide. Identification of non-lethal, low phytic acid mutations in corn, and more recently barley, result in a substantial reduction in phytic acid, with a corresponding increase in inorganic phosphorus. In the present study, four varieties of the low phytic acid (LP) barley including LP 422, LP 635, LP 955 and LP 1070 and a conventional barley (CDC DOLLY) were examined with broiler chickens from 2 to 17 days of age. LP barley lines exhibiting a range of various phytic acid reduction indicated increasing phosphorus retention (P<0.01), which was reflected by increasing tibia ash in phosphorus deficient diets. Phosphorus excretion was reduced accordingly (P<0.01). Body weight gain (P<0.05) and feed conversion (P<0.01) also improved with phytic acid reduction; feed conversion in particular was significantly better for chicks given the lowest phytic acid barley line (LP 955) than a commercial variety. Retention of major nutrient fractions (phosphorus excepted; dry matter, fat, protein, amino acids) indicated no significant effect with phytic acid reduction.

Studying broiler preference to feed color is important for improving comfort and welfare of broilers and it may be beneficial for improving performance. The aim of the first experiment was to examine day-old chick's preference in different light colors to different feed colors. One hundred and sixty Ross 308 newly hatched broilers, never exposed to feed, were allocated into pens illuminated with different light colors: white, yellow, green and red. Under each color of light four colored feed choices (red, green, yellow and control) were offered. Choice was recorded the moment the bird attempted to obtain feed. In the second experiment, 80 chicks were chosen and separated equally in four pens illuminated with white color. Light intensities were the same in all pens at both experiment. The pens were separated using black plastic to keep stray light from interfering with neighboring pens. In each pens there were 4 dishes containing different feed color and chicks were allowed to choose the preferred color of feed for consumption. All chicks were fed a standard NRC ration and all pens were given ad libitum access to feed and water. The amount of feed intake from each colored feed in each pen was determined as a proportion of total pen feed intake until 21th days of rearing period. The results indicated that there were no significant differences between preferences of chicks to different feed colors. However, it was observed that under white light chicks tend to prefer green feed compared to control (P=0. 08). The results in the second part of experiment showed that the feed intake from green feed were significantly higher compared to other colored feeds. Also, birds had the lowest proportion of feed intake from the red-colored ration under white lighting.

Nanoparticle of Silver, with creating free radicals, can destroy many bacteria, viruses and fungi; therefore they have been recommended as a disinfectant in livestock’s production system. In this study 240 Ross 308 strain chicks in a completely randomized design (CRD) in four treatments at 0(control), 4, 8 and 12 ppm levels of silver nanoparticles in drinking water with four replicates within 16 separate floor pens and 15 birds in each pen were reared. At the end of growing period from each pen two broilers with the average weight were selected and after taking blood sample, sacrificed and their kidney were examined with light microscope by H&E staining. Histopathology showed dose depended changes such as congestion, presence of inflammatory cells including heterophile and lymphocytes, necrosis in tubular cells, proliferative glomerulonephritis and fibrosis. Lesions in the treatments 3 (8ppm) and 4 (12ppm) were more sever than the group 2 (4ppm). Also, increased serum uricacid in treatment 4 (12ppm) compared to control group was significant (p<0.05). It can be concluded that using of nanosilver higher than 8ppm in drinking water can induce sever lesions in kidney of chickens.

Heat stress remains a major challenge for the poultry industry, particularly in tropical regions and warm seasons, where it negatively impacts poultry welfare and performance, leading to economic losses. Although heat stress has been a long-term concern for the poultry industry, existing solutions only partially alleviate the negative impacts on overall productivity. Enhancing our understanding of this challenge and available solutions can aid in shaping future initiatives to develop more robust solutions for managing heat stress. This review explores recent strategies developed to mitigate heat stress in broiler chickens, including genetic selection, nutritional approaches such as vitamins (C, E, A, and B groups), amino acids, electrolytes, environmental modifications, and improving behavioral monitoring systems. Furthermore, we discussed the challenges in reducing the impacts of heat stress. Integrating these diverse strategies can improve poultry resilience, ensuring better welfare and sustainable production systems. Therefore, this review contributes to advancing adaptive strategies to safeguard poultry in a warming world.

Introduction3: Essential amino acids comprise 10 to 13% of the poultry diet. Methionine is the first limiting amino acid that plays important roles in protein metabolism and immune functions in chickens. Previous studies have shown that the appropriate level of methionine in the diet increases the growth and it is essential for enhancing the immune response. Methionine is also requirement to increase the function of the T cells produced from the thymus. Methionine has beneficial effects on the immune system and improves both humoral and cellular immune responses. Interferongamma (IFN- ) is one of the components of group-specific immune cytokines and an important activator of macrophages. IFN- is known as cytokine which it is critical for innate and adaptive immunity against viral, some bacterial and protozoa infections. The aim of present study was to investigate effect of different diet levels of methionine on immune system and IFNγ gene expression in broiler chickens. Materials and Methods: This study was conducted in a completely randomized design with six experimental groups with 4 replicates and 20 observations in each replicate. The difference was in the levels of dietary methionine in the growth period, which included experimental groups 0. 29, 0. 36, 0. 43, 0. 51, 0. 57 and 0. 64%. The antibody produced against the sheep's red blood cell, white blood cell differential counts and the volume percentages of red blood cells were determined. In order to determine the IFNγ gene expression, the whole RNA was extracted from the liver tissue of different treatment chickens. Then, cDNA was synthesized and the expression of the IFNγ gene was evaluated using Real Time PCR. In this study, design of primers (GAPDH and IFNγ ) was performed using primer premier software version 5 to evaluate IFNγ gene expression in broiler chickens. Real-time PCR was performed using SYBER Green qPCR Master Mixes (Thermo) in Lightcyclear 96 (Roche). Melting curve of IFN and GAPDH gene productions were drawn using Real Time PCR for broiler chickens. The relative gene expression was quantified by the 2-Δ Δ ct method. The results were analyzed by GLM method of SAS software. Tukey post hoc test was used to compare the means of the experimental groups at the significant level of 0. 05. Results and Discussion: The results showed that response to sheep's red blood cell, immunoglobulin G, immunoglobulin M, white blood cells, heterophile, lymphocyte and heterophile to lymphocyte ratio were not affected by different levels of methionine, but the number of red blood cells was affected by different levels of methionine, so that the highest number of red blood cells associated to methionine level was 0. 29% and the lowest value was 0. 57%(p≤ 0. 05). The result of the absorption measurement of the extracted RNA samples at a wavelength of 280/260 was in a range of 1. 8 to 1. 9 mm, indicating the desired quality of extracted RNA. The result of melting curve of Real Time PCR and PCR products on agarose gel showed that the IFNγ and GAPDH genes were amplified in the liver tissue. The observation of band at 259 bp for the IFNγ and at 264 bp for the GAPDH gene for all samples indicates the correctness of the test and the amplification of the desired fragments. The expression results showed that there was a significant increase in IFNγ gene expression with increasing methionine levels from 0. 29% to 0. 43% and higher levels (p≤ 0. 05). However, there was no significant difference between the levels of methionine 0. 43 to 0. 64%. Regarding the fact that the present study was carried out under normal conditions without disease challenges, etc., different levels of methionine not effect on the immune system. IFN-γ gene is a type of cytokine. Cytokines do not exist as precursor molecules, and their production begins with transcription of the genes. This transcription activity is usually temporary and mRNA coding for cytokines is unstable and if the immune system is stimulated by the pathogen, Innate immune is the first hostile defense way. After detecting pathogens, host cell receptors such as Toll-like and nucleotide oligomers that include receptors are able to transmit a variety of signals, and subsequently cytokine gene expression networks begin to function until the innate immune responses begin. Conclusion: The results showed that IFN-γ gene expression was significantly increased by increasing methionine levels from 0. 29% upwards. Perhaps one of the reasons for increased IFN2 gene expression in this study is the application of appropriate methionine levels in experimental treatments and the benefits of appropriate methionine levels in the diet to enhance immune function in the bird, although the present study was conducted under normal growing conditions and without the challenge of pathogens.