Seyed Abolghasem Fatemi

In ovo injection has emerged as a targeted strategy for delivering essential nutrients or vaccines during avian embryogenesis, yet the effects of vitamin D (VitD) metabolites delivered prior to hatch remain incompletely understood. This review summarizes the available evidence describing the embryonic and post-hatch responses of broilers when VitD is administered in ovo and highlights the opportunities and limitations for improving their performance in association with each VitD source, including vitamin D₃ (VitD₃), 25-hydroxyvitamin D₃ (25OHD₃), 1α-hydroxyvitamin D₃ (1α-OHD₃), 1,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃), and 24,25-dihydroxyvitamin D₃. Greater post-hatch improvements in broiler performance and skeletal development have been observed when in ovo 25OHD₃ was combined with dietary 25OHD₃ or minerals. The in ovo delivery of 1.2 to 2.4 µg of water-soluble 25OHD₃ alone or in combination with Marek’s disease vaccine between 17.5 and 18 days of incubation (doi), has been found to be effective in improving hatchability, post-hatch performance, bone mineralization, meat yield, intestinal histomorphology, and immune function. In contrast, in ovo administration of 1α-OHD₃ and 1,25(OH)₂D₃ at low doses has resulted in inconsistent performance and remains unsuitable for practical in ovo application. The physiological responses to in ovo VitD sources are highly dependent on metabolite form, dose, solubility, vehicle, embryonic age at administration and post-hatch environmental conditions. Nevertheless, 25OHD₃ is a promising candidate for integration into commercial in ovo platforms. Furthermore, knowledge gaps remain for defining optimal dose ranges, understanding metabolite interactions, and evaluating long-term impacts across different production systems.

The environmental and health concerns of traditional preservatives have led to investigations into an effective solution for protecting wood products with preservatives from natural sources. Guayule resin, derived from the Parthenium argentatum plant, has been reported to be effective as a wood preservative due to its bioactive properties. However, its high viscosity, limited penetration, and unknown leaching behavior may affect its durability and efficiency. This study investigated guayule resin concentration and solvent carrier efficacy. Yellow poplar and southern pine specimens were treated with guayule resin at four concentrations in three different solvents including acetone, ethyl acetate, and toluene. The leaching test was performed according to the AWPA E11-16 standard. Significant interaction between solvent type and concentrations of guayule resin were found in both species in which a lower mass loss was observed when 5% concentration of guayule combined with toluene as compared to any other guayule concentrations in southern pine. On yellow poplar specimens, 0.5% concentration of guayule in combination with toluene exhibited lower mass loss as compared to any other guayule concentration. In conclusion, toluene was found to be the best performing polar carrier system for guayule resin, considering its functionality and dose-dependence in both species.

Optimal commercial conditions have been shown to improve the performance and meat yield of broilers. Also, dietary 25-hydroxycholecalciferol (25OHD₃; crystalline form) has not shown a negative impact on chicken health when it was fed at 10 times (10×) higher than 69 μg/kg. The objectives of this study were to determine the effects of up to 8 times (8×) higher than the commercial level (69 μg/kg of feed) of dietary 25OHD₃ on the performance, breast meat yield, and serum 25OHD₃ concentration of broilers. Eighteen male chicks were randomly assigned to each of 20 pens within each of the two dietary treatments. Treatments were commercial diets containing 250 IU/kg of vitamin D₃ (control) for the starter [(0 to 14 days post-hatch (poh), grower (15 to 28 poh), and finisher (29 to 42 poh) dietary phases; or diets containing Hy-D (water-soluble source of 25OHD₃) that consisted of 552 (8×) μg/kg of 25OHD₃ for the starter, 276 (4×) μg/kg of 25OHD₃ for the grower, and 34.5 (0.5×) μg/kg of 25OHD₃ for the finisher dietary phases. Live performance variables as well as serum 25OHD₃ concentrations were measured in each dietary phase. At 14, 28, and 39 poh, breast meat yield that included pectoralis major (P. major) and pectoralis minor (P. minor) muscle weights was determined in ten replications per dietary treatment. Breast yield was also calculated by adding the values of the P. major and P. minor muscles. From 14 to 42 poh, the Hy-D diets decreased (p < 0.0001) broiler body weight (BW) and BW gain and increased (p < 0.0001) total mortality and feed conversion ratio in comparison to control treatment groups. In addition, birds fed Hy-D diets had significantly (p < 0.0001) lower P. major and breast meat yields from 14 to 39 poh as compared to those birds fed the control diet. Serum 25OHD₃ concentration was significantly (p < 0.0001) higher (10×) in birds that belonged to the Hy-D diet treatment than those in the control diet treatment group. These results indicate that the disproportionally high (8×) level of dietary 25OHD₃ resulted in detrimental effects on the performance and meat yield of broilers. A reduction in both performance and meat yield of broilers in response to the elevated level of dietary 25OHD₃ may have been due to vitamin D₃ toxicity, which can result in an association with the overproduction of the active form of the vitamin in response to elevated serum concentrations of 25OHD₃.

Effects of in ovo and dietary sources of calcidiol (25(OH)D₃), combined with Marek’s disease vaccine (MDV), on the expression of genes involved with the antioxidant activity, muscle deposition, and immunity in the pectoralis major (P. major) muscle and spleen of 40 d of age (doa) broilers were investigated. The in ovo treatments were as follows: (1) non-injected; (2) the injection of 50 μL of commercial MDV, (3) MDV + 1.2, or (4) 2.4 μg of 25(OH)D₃. All birds received either a commercial diet containing no supplemental 25(OH)D₃ (control) or the same diet supplemented with an additional 69 µg of 25(OH)D₃ per kg of feed (Hy-D diet). At 40 doa, the pectoralis major (P. major) muscle and spleen of 48 birds (six replicates per diet x in ovo treatment combination) were collected. When compared to un-supplemented commercial diet-fed birds, in birds that were fed the Hy-D diet, the expression of the TGF-β4 gene in the spleen and P. major muscle, and the GSH-P1, GSH-P7, SOD2, MyoG, MyoD1, and Pax3 genes in the P. major muscle were up-regulated, whereas the expression of the IL-1β, IL-8, and CYP24A1 genes in the spleen and P. major muscle were down-regulated. Nevertheless, birds that received any of the in ovo injection doses of 25(OH)D₃ exhibited a higher expression of the IL-10, TGF-β4, and CYP27B1 genes in the spleen and P. major muscle. Furthermore, in comparison to the MDV-injected control group, the CAT, MyoD1, and Pax3 genes in the P. major muscle were up-regulated, and the expression of the INF-γ, IL-1β and CYP24A1 genes in the spleen and the IL-8, and IL-1β genes in the P. major muscle were down-regulated. In conclusion, a significant improvement in the expression of genes responsible for enzymatic antioxidant activity, protein synthesis, and inflammatory reactions in 40-day-old broilers occurred in response to in ovo and dietary supplemental 25(OH)D₃, and supplemental 25OHD₃ provided via either route was used to enhance the expression of genes linked to vitamin D activity (CYP27B1, CYP24A1).

The effects of the Marek’s disease vaccine (MDV) on the live performance, breast meat yield, and incidence of woody breast myopathy (WBM) of Ross 708 broilers were investigated when administered alone or in conjunction with in ovo and dietary supplemental 25-hydroxycholecalciferol (25OHD₃). At 18 d of incubation (doi), four in ovo injection treatments were randomly assigned to live embryonated Ross 708 broiler hatching eggs: (1) non-injected; (2) commercial MDV alone; or MDV containing either (3) 1.2 or (4) 2.4 μg of 25OHD₃. An Inovoject multi-egg injector was used to inject a 50 μL solution volume into each egg. The birds were provided a commercial diet that contained 250 IU of cholecalciferol/kg of feed (control) or a commercial diet that was supplemented with an additional 2760 IU of 25OHD₃/kg of feed (HyD-diet). In the growout period, 14 male broilers were placed in each of 48 floor pens resulting 6 replicated pens per in ovo x dietary treatment combination. Live performance variable were measured at each dietary phases from 0 to 14, 15 to 28, and 29 to 40 d of age (doa). At 14 and 40 doa, pectoralis major (P. major) and pectoralis minor (P. minor) muscles were determined for one bird within each of the six replicate pens. At 41 doa, WBM incidence was determined. No significant main or interaction effects occurred for WBM among the dietary or in ovo injection treatments. However, in response to in ovo 25OHD₃ supplementation, BW and BWG in the 29 to 40 doa period and BWG and FCR in the 0 to 40 doa period improved. In addition, at 40 and 41 doa, breast meat yield increased in response to in ovo and dietary 25OHD₃ supplementation. Future research is needed to determine the possible reasons that may have been involved in the aforementioned improvements.