Pros and Cons of Dietary Vitamin A and Its Precursors in Poultry Health and Production: A Comprehensive Review.

Vitamin A is a fat-soluble vitamin that cannot be synthesized in the body and must be obtained through diet. Despite being one of the earliest vitamins identified, a complete range of biological actions is still unknown. Carotenoids are a category of roughly 600 chemicals that are structurally related to vitamin A. Vitamin A can be present in the body in the form of retinol, retinal, and retinoic acid. Vitamins are required in minute amounts, yet they are critical for health, maintenance, and performing key biological functions in the body, such as growth, embryo development, epithelial cell differentiation, and immune function. Vitamin A deficiency induces a variety of problems, including lack of appetite, decreased development and immunity, and susceptibility to many diseases. Dietary preformed vitamin A, provitamin A, and several classes of carotenoids can be used to meet vitamin A requirements. The aim of this review is to compile the available scientific literature regarding the sources and important functions, such as growth, immunity, antioxidant, and other biological activities of vitamin A in poultry.

Interaction of blood calcium with luteal activity, energy metabolites and somatic cells count in post-partum dairy cows.

The aim of the research was to assess whether there was a link between serum calcium (Ca) after calving and serum progesterone, milk somatic cells count and Ca, and other blood metabolites in Achai and crossbred cows. Based on blood calcium level shortly after calving, thirty cows from both breeds were divided into a moderate group (≤10.0 mg/dl of Ca) and a high group (>10.0 mg/dl of Ca), with samples collected at 0, 7, 14, 21, 28 and 35 days post-partum, respectively. On day 35 of the post-partum, crossbred and Achai cows with high blood Ca recorded significantly (p < .01) higher serum progesterone, glucose, triglyceride and milk Ca compared with moderate blood Ca group; however, serum cholesterol was significantly (p < .01) higher in both breeds under high blood Ca. Incidence of subclinical mastitis was significantly (p < .01) higher in crossbred and Achai cows under high blood Ca. The results showed that blood progesterone (OR=2.095), glucose (OR=1.024), triglyceride (OR=4.571), cholesterol (OR=1.111) and milk Ca (OR=1.141) resulted in a greater concentration in crossbred compared to Achai cows. A significant (p < .01) correlation was found between blood Ca and other blood metabolites (progesterone, glucose, triglyceride and cholesterol) in both breeds. In conclusion, greater serum Ca concentration after calving is associated with greater serum progesterone, glucose, triglyceride and milk Ca in crossbred cows; however, the incidence of subclinical mastitis increased.

Evaluating productive performance, meat quality and oxidation products of Italian White breed rabbits under free-range and cage rearing system.

OBJECTIVE: Free-range systems have been increasingly available to the consumer due to increased demand for more sustainable meat-products. In the current study, the effect of free-range (FR) and cage system (CS) was explored on growth performance, meat quality and oxidation products in Italian White breed rabbits during the growing-fattening phase (5 to 13 weeks of age). METHODS: Forty rabbits were randomly allotted to two treatment groups according to the rearing system, and each treatment group was replicated five times with four subjects in each replicate (20 rabbits per treatment-group). All rabbits fed the same diet as pelleted, and under FR system, no additional feeds were available to animals. RESULTS: Rearing system had significant effect on rabbit growth performance, where CS group resulted in higher final body weight (p<0.045) and gain (p<0.029) and better feed efficiency (p<0.025) compared to FR rabbits. Most carcass traits were not affected by rearing system; however, a reduction of abdominal fat content (p<0.015) and meat lipids (p<0.034) was observed in FR rabbits. Rearing system had no effects on meat fatty acid profile, whereas meat from FR rabbits resulted less susceptible to lipid and protein oxidation compared to caged animals. CONCLUSION: In overall, FR system could be suggested as a substitute for conventional caged system because of FR system preserved rabbit meat from oxidation.

Effect of dietary sesame (Sesame indicum L) seed meal level supplemented with lysine and phytase on performance traits and antioxidant status of late-phase laying hens.

OBJECTIVE: This study was performed to investigate the effects of supplementing sesame seed meal (SSM) with phytase and lysine on performance, egg quality, blood biochemical and antioxidant status of laying hens. METHODS: A total of 960, 56-wk-old laying hens were divided into 12 dietary groups with eight replicates per group (10 birds per replicate). A completely randomized design with factorial arrangement 2×3×2 consisted of two levels of lysine supplement (0 and 10% over requirement), three SSM levels (0, 10 and 20%) with or without phytase (0 and 300 g/ton). The feeding trial lasted 10 weeks. RESULTS: From findings, birds fed diets with 10% SSM had higher feed intake than groups fed 0 and 20% SSM. The addition of phytase to experimental feeds, improved feed conversion ratio (FCR), increased egg weight and mass (P&lt;0.01). Egg quality criteria was not affected by supplementing phytase; however, supplementing 300 g/ton phytase to hens diet, led to a significant (P&lt;0. 05) increase in egg shell strength. Egg yolk cholesterol and serum low-density lipoprotein cholesterol (LDL-C), atherogenic index and total cholesterol were decreased (P&lt;0.01) by diet containing 20% SSM. The high-density lipoprotein cholesterol (HDL-C) was increased (P&lt;0.05) in serum of hens fed 20% SSM than the other groups. It was also observed that total antioxidant capacity (TAC) and total superoxide dismutase (TSOD) content of hens fed 20% SSM was significantly upper than control group (P&lt;0.05). CONCLUSION: As from results, dietary supplementation of SSM and phytase had no negative effects on laying hens performance or egg quality improving also the egg oxidative stability.

Summer Savory (Satureja hortensis L.) Extract as Natural Feed Additive in Broilers: Effects on Growth, Plasma Constituents, Immune Response, and Ileal Microflora.

This study investigated the effects of summer savory (Satureja hortensis L.) extract (SSE) on growth, plasma constituents, immune response, and gut microbiota of broiler chickens. A total of 300 day-old broiler chicks were randomly assigned to five dietary treatments containing five replicates of 12 birds each. The treatments consisted of a controldiet without feed additive and experimental diets supplemented with four levels of SSE (100, 200, 300, and 400 mg/kg, respectively). Results showed no significant effect of SSE supplementation on broiler body weight gain (p > 0.05), but feed conversion ratio was significantly (p < 0.05) improved when fed 400 mg/kg SSE compared to control. Most of the blood parameters and immune response criteria studied were improved (p < 0.05) by SSE supplementation. There was no dietary effect on Lactobacilli count (p > 0.05); conversely, Escherichia coli count was reduced and the Lactobacilli/E. coli ratio improved with SSE (p < 0.05). Based on our findings, it was concluded that supplementation of the diet with SSE up to 400 mg/kg sustained growth traits and improved the feed efficiency and health status of broilers. However, more research is needed on this subject in order to better understand the mode of action of the extract used.

Performance and carcass measurements of ewe lambs reared in a feedlot and fed wheat (Triticum durum Desf.) middlings total mixed rations in the summer season.

The effect of total mixed ratios containing wheat middlings (WM) as a corn grain substitute on the growth performance and carcass traits of Comisana ewe lambs was evaluated. Forty ewe lambs, with average live body weight of 13 ± 0.3 kg (mean ± SEM), were allocated randomly to two isocaloric and isonitrogenous diets for 50 days. Control diet contained 400 g/kg of dry matter (DM) of corn as the main starchy source, whereas experimental diet contained 600 g/kg DM of WM. In vivo nutrient apparent digestibility of the two diets was determined using Comisana rams (mean body weight, 65 ± 2.3 kg) and indicated significant (P < 0.05) differences for neutral detergent fibre, acid detergent fibre, cellulose and hemicellulose fractions. Results from the trial using Comisana ewe lambs showed that growth traits were unaffected by dietary treatments as well as none of the carcass measurements examined (P > 0.05). These findings indicate that WM results as a suitable feed ingredient for growing ewe lambs that can be a satisfactory substitute to conventional grain source.