Vito Laudadio

Effect of vitamin E in heat-stressed poultry

Heat stress is associated with compromised performance and productivity in poultry due to declines in feed intake, nutrient utilisation, growth rate, egg production and quality, feed efficiency and immunity. Additionally, heat stress is characterised by reduced antioxidant status in birds, resulting in increased oxidative stress. Heat stress is also linked with increased economic losses due to mortality of birds. Vitamin E is a major chain-breaking antioxidant in biological systems. An optimum response with supplementation of vitamin E in feed has been found to improve feed intake, body weight gain, feed efficiency, egg production and quality, nutrient digestibility, immune response and antioxidant status in poultry birds. This work compiles past and present information about the role of vitamin E in heat-stressed poultry.

Productive performance and histological features of intestinal mucosa of broiler chickens fed different dietary protein levels

To evaluate the effect of decreasing dietary protein on growth performance, carcass traits, and intestinal mucosal morphometry, 180 female Hubbard strain broiler chickens were divided into 3 groups and fed 3 isoenergetic diets ad libitum from 14 d of age until slaughter age (49 d). The treatments varied according to 3 protein levels: high-protein diet (HiP, 22.5% CP, DM basis), medium-protein diet (MedP, 20.5% CP), and low-protein diet (LowP, 18.5%). Diets were obtained by replacing wheat middlings with soybean meal and were formulated to meet or exceed broiler amino acid requirements of the NRC. Morphometric indices of duodenum, jejunum, and ileum were measured at the end of the feeding period and included villus height, crypt depth, villus-to-crypt ratio, and apparent villus surface area. The dietary protein level had a significant effect on final BW of birds, whereas ADG, ADFI, and feed efficiency remained unaffected by dietary treatment. The muscle (breast and drumstick) yields were significantly higher in birds fed the HiP diet compared with those of the MedP and LowP diets. Meat quality traits were not affected by the protein level. The villus surface area of all intestinal segments did not change among groups. Instead, reducing the dietary protein level to 20.5% resulted in a higher villus height and villus height to crypt depth ratio in the duodenum and ileum. On the basis of our findings, even if the high-protein diet promoted meat yield, a medium-protein diet could positively support broiler growth performance, as confirmed by favorable morphometric features of the intestine.

Effect of ascorbic acid in heat-stressed poultry

Two reviews are available in published literature relating to the effects of ascorbic acid on poultry performance. The first review was written by Pardue and Thaxton in 1986 who reviewed the role of ascorbic acid in alleviating the negative effect of heat stress in poultry birds. The second review was presented by Whitehead and Keller in 2003, who detailed the general effects of ascorbic acid in poultry birds, not taking into consideration ‘heat stress’. The first review is deficient in the literature published after 1986, while the second review does not describe the effect of ascorbic acid in heat stressed birds. The present review describes the past and present knowledge of ascorbic acid in alleviating heat stress in poultry birds with new aspects. Heat stress is associated with compromised performance and productivity through a decline in feed intake, nutrient utilisation, growth rate, egg production and quality, feed efficiency and immunity. Heat stress is also characterised by a reduced antioxidant status in birds, resulting in increased oxidative stress. Moreover, male fertility is decreased when birds are exposed to heat stress. Supplementation of 250 mg of ascorbic acid per kg of feed has been found to be optimum to improve feed intake, body weight gain, feed efficiency, egg production and quality, nutrient digestibility, immune response and antioxidant status in poultry birds. This work compiles past and present information about the role of ascorbic acid in heat-stressed poultry.

Growth performance and carcass and meat quality of broiler chickens fed diets containing micronized-dehulled peas (Pisum sativum cv. Spirale) as a substitute of soybean meal

An experiment was carried out to evaluate the effects of diets containing peas on productive traits, carcass yields, and fatty acid profiles (breast and drumstick meat) of broiler chickens. Hubbard strain broiler chicks, divided into 2 groups, received from 14 d to slaughtering age (49 d) a wheat middlings-based diet containing soybean (190 g/kg) or micronized-dehulled peas (400 g/kg) as the main protein source. The inclusion of peas did not significantly change the growth performance of birds. The pea level had no effect on the dressing percentage, the percentage of breast or drumstick muscles, and abdominal fat. The muscles of birds fed the pea diet had significant (P < 0.05) lower L* (lightness) and b* (yellowness, drumstick muscle) values and fat content. Instead, total collagen and water-holding capacity values were higher in the pea treatment. The polyunsaturated fatty acid concentration in breast and drumstick muscles was significantly increased with the alternative protein source inclusion, whereas the saturated fatty acid was similar among treatments. The n-6/n-3 polyunsaturated fatty acid ratio of the broiler drumstick meat decreased significantly in the pea group. Dietary pea inclusion improved the saturation index of meat without altering atherogenic and thrombogenic indexes. It can be concluded that the pea treatment tested had a positive effect on the performance and meat quality of broiler chickens.

EFFECT OF REDUCING DIETARY PROTEIN LEVEL ON PERFORMANCE RESPONSES AND SOME MICROBIOLOGICAL ASPECTS OF BROILER CHICKENS UNDER SUMMER ENVIRONMENTAL CONDITIONS

This study examined the effect of different crude protein (CP) levels in the diet on growth performance of broilers as well as the total aerobic mesophilic count (TAMC) and Escherichia coli count (ECC) isolated from chicken faeces. A total 150 day-old broilers (Hubbard) were allocated to three treatments with five replicates containing 10 birds. The dietary treatments consisted of three diets with different CP levels for 42 days: high-protein (HCP, 22.5%), medium-protein (MCP, 20.5%), and low-protein (LCP, 18.5%). Body weight and feed intake were determined and the feed conversion ratio was calculated. Faecal samples were collected at 14, 21 and 42 days. Dietary CP did not affect the growth performance of broilers. Reducing CP level was effective at beneficially modulating the composition of the faecal microflora, in particular TAMC and ECC concentrations (log10 CFU g−1) were significant lower for the LCP birds. During hot temperature conditions (33°C and 70% relative humidity) a low protein diet may help to control the characteristics of the faecal microbial community without negative effects on broiler performance.

Major proteins in goat milk: an updated overview on genetic variability

Milk and dairy products are very important in Mediterranean diet because of their health promoting and organoleptic properties. In many developing countries, goat rearing has a key role in livestock production. What makes goats so popular is their ability to provide high quality food under diverse climatic conditions and resilience to extreme and capricious environments. In the last years, the interest concerning caprine milk has been increasing also to find a new exploitation for local breeds. To promote the goat dairy products there is a clear need to know the quality and the technological aspects of milk produced. That being so, the purpose of this study was to review the available literature on the major goat milk proteins with a particular attention to recent findings on their genetic variability. Moreover, the main effects of different protein variants on milk yield and composition were also discussed.

Garlic ( Allium sativum ) supplementation in poultry diets: effect on production and physiology

Poultry researchers and nutritionists are looking for viable alternative feed additives since conventional supplements have been criticised for their potential negative impact on the food chain. Among the currently available poultry feed additives, natural herbs and plants have been widely advocated due to their reported widespread beneficial effects. Garlic (Allium sativum) is one such potential feed supplement which has recently been reported as having a wide range of beneficial effects on the production performance and physiological biochemistry of broilers and laying hens. Notable beneficial effects have been seen on growth, feed efficiency, egg production and quality, as well as stimulation of immune system and lowering blood cholesterol levels in poultry birds. The results reported vary from author to author probably due to variations in the dose of the product fed, the duration of feeding and processing techniques employed.

A survey of chemical and nutritional characteristics of halophytes plants used by camels in Southern Tunisia

The camel (Camelus dromedarius) is well adapted to the utilization of vegetation of low nutritional value in its natural habitat zone, thanks to its aptitude to vary food and to search plants that are rich in water content and that can make up for its nutritional deficits, particularly as concerns mineral elements. Therefore, a survey was carried out to determine camels pasture quality, dietary preference and to characterize the chemical characteristics and nutritional value of different halophytes plants in a region of Southern Tunisia during spring season. Laboratory analysis were conducted on fourteen vegetable species appertained to seven different botanical families: Chenopodiaceae, Graminaceae, Tamaricaceae, Zygophyllaceae, Asteraceae, Frankeniaceae and Plumbaginaceae. Data obtained indicate an high variability of nutritional content of halophytes plants preferred by camels, specially for dry matter, crude protein, fiber fractions, ash and mineral elements.

THYMUS VULGARIS: ALTERNATIVE TO ANTIBIOTICS IN POULTRY FEED

Due to the potentially undesirable effects of antibiotics as growth promoters in poultry production, researchers are looking for viable alternative to limit or replace their use. One such class of comparable alternative is natural source of herbs and medicinal plants. In the last decade, these alternatives have been increasingly used in broiler, layer and Japanese quail diets. Reports have variously claimed that medicinal plants, used as either the whole plant, their leaves or flowers, can enhance poultry performance. From the available literature, it can be concluded that thyme (Thymus vulgaris) belongs to such class of medicinal plant and may be an effective alternative to antibiotics in poultry production. In this review, its effects on different parameters of production performance in poultry are briefly discussed.

Treated fava bean (Vicia faba var. minor) as substitute for soybean meal in diet of early phase laying hens: Egg-laying performance and egg quality

The objective of this study was to determine the effect of dietary dehulled-micronized fava bean (Vicia faba var. minor) seed on egg production, egg weight, feed conversion ratio, eggshell quality, and egg yolk color. In this trial, 18-wk-old laying hens in the early phase of production (ISA Brown) were randomly assigned to 2 groups and fed durum wheat middlings-based diets containing soybean or micronized-dehulled fava bean meal as the main protein source. Eggs were collected and weighed daily. Laying performance, egg quality, and feed conversion ratio were evaluated for 10 wk. The only significant effect detected was for feed intake (P<0.05), which was lower in hens fed the diet containing fava bean than for hens fed soybean meal, without however any negative effects on feed efficiency. None of the egg quality parameters studied were influenced by dietary treatment, except for yolk color score that was reduced in hens fed the fava bean diet (P<0.05). We conclude that dehulled-micronized fava beans in the diet did not have a negative influence on productive performance or egg quality of young brown hens.