Effect of stocking density and vitamin E or zinc supplementation on growth, physiology, gene expression, and economic efficiency of growing broiler chicks

A total of 636 1-day-old male Cobb chicks were randomly assigned to seven treatments. The chicks were offered feed and water ad libitum throughout the experimental period. The first three groups included different stocking densities of broiler birds (low stocking density, LSD: 23 kg/m²; medium stocking density, MSD: 34 kg birds/m²; and high stocking density HSD: 39 kg birds/m²). The LSD group was considered a control group. The other four groups included MSD or HSD broiler birds supplemented with either Vit E (100 mg/kg DM diet; MSDVE and HSDVE) or Zn (100 mg/kg DM diet; MSDZn and HSDZn) in their basal diet. The main findings indicated that HSD and MSD negatively affected (p < 0.05) all variables under investigation compared with LSD. Compared with LSD, broiler birds in the MSD and HSD groups had lower body weights and higher feed conversion ratios, higher concentrations of blood plasma hormones (triiodothyronine thyroxine and corticosterone), and downregulated expression levels of hepatic growth hormone and insulin-like growth factor-l. In addition, broiler birds stocked at medium or high densities resulted in less economic return and profit. Vit E or Zn supplementation to broiler birds stocked at medium or high densities significantly reversed all adverse effects of HSD (> 23 kg/m²) on growth performance, hormones, and gene expression. It could be recommended that adding Zn at a level of 100 mg/kg per DM diet allows increasing the stocking density of broiler birds from 23 kg/m² to 34 birds/m² while maintaining the birds, welfare and economic profit.

Growth performance, economic efficiency, meat quality, and gene expression in two broiler breeds fed different levels of tomato pomace

Male broiler chicks (135 Indian River chicks (IR) and 135 Cobb chicks; n = 270) were weighed, wing banded, and distributed randomly into three iso-energetic and iso-nitrogenous diet groups for each breed (triplicate design, 45 bird/group, 15 bird/replicate). The chicks were fed the diets with levels of 0, 4, or 6% sun-dried tomato pomace (SDTP), respectively, for 42 consecutive days to determine the effect of consuming different levels of SDTP on growth performance, economic efficiency, meat quality, and gene expression in IR and Cobb broiler chickens. The inclusion of up to 6% SDTP in the diet of IR or Cobb chickens had no negative impact on growth performance parameters. Chickens from both the IR and Cobb breeds fed a diet containing 4% or 6% SDTP consumed more feed than those fed a diet containing 0% SDTP. Concomitantly, the groups fed a 6% SDTP diet of IR breed incurred a significantly higher feed cost, total variable cost (TVC), and total cost (TC). The inclusion of up to 6% SDTP in the feed of both breeds resulted in a non-significant increase in return parameters. The ultimate pH decreased as the SDTP concentration increased, with no significant differences in water holding capacity (WHC) or drip loss (48 h). No alteration in the mRNA expression of hepatic growth hormone receptor gene (GHR) or insulin like growth factor-1 (IGF-1) was found among the treatments for either the IR or Cobb breeds. Thus, up to 6% SDTP can be added to the diet of IR and Cobb broiler chickens without any adverse effects on the examined parameters.

Ameliorative Effect of Neem Leaf and Pomegranate Peel Extracts in Coccidial Infections in New Zealand and V-Line Rabbits: Performance, Intestinal Health, Oocyst Shedding, Carcass Traits, and Effect on Economic Measures

Healthy, weaned, coccidial-free male rabbits from two breeds (New Zealand white (NZ) and V-line (VL)) were divided into 10 equal groups (5 groups each for NZ and VL) (3 replicates/group, 6 rabbits/replicate, 18 rabbits/group). All rabbits were inoculated with 5 × 10⁴&nbsp;Eimeria spp. oocysts (E. intestinalis (67%), E. magna (22%), and E. media (11%)) except for the rabbits in the first group (G1), which were inoculated with a sterile solution and served as a negative control. The remaining four groups were treated as follows: G2, no treatment/positive control, G3, treated with neem leaf extract, G4, treated with pomegranate peel extract (PPE), and G5, treated with a combination of neem leaf extract and PPE. For both breeds, our results showed that the use of neem leaf and/or pomegranate peel extract resulted in improved growth performance, with a significant improvement in relative feed conversion ratio (FCR) compared to the positive control groups, which recorded the worst values, as well as a significant (p ≤ 0.05) reduction in mean oocyst count compared to the positive control groups. We also observed downregulation of mRNA levels of IL-1βα, IL6, and TNF-α in the herbal treatment groups compared with the mRNA levels of these genes in the positive control groups. Herbal treatment with neem leaf and/or pomegranate peel extracts had positive effects on the NZ and VL rabbits experimentally infected with mixed Eimeria species, as evidenced by their healthy appearance, good appetite, no mortalities, an anticoccidial index > 120, and a significantly higher total return and net profit when compared to the positive control groups of both breeds. In NZ rabbits, the treatment with neem leaf extract alone (G3) or in combination with PPE (G5) recorded the most efficient economic anticoccidial activity.