Effects of the in ovo injection of VitD3 and 25-hydroxyvitamin D3 in Ross 708 broilers fed commercial or calcium and phosphorus-restricted diets. I. Performance, carcass characteristics, and incidence of woody breast myopathy

Authors: FATEMI, S - Mississippi State University; ALGHTANI, A - Mississippi State University; Collins Elliott, Katie; BELLO, A - University Of Alberta; ZHANG, H - Chinese Academy Of Agricultural Sciences; PEEBLES, E - Mississippi State University

Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/18/2021
Publication Date: 6/30/2021
Citation: Fatemi, S.A., Alghtani, A., Collins Elliott, K.E., Bello, A., Zhang, H., Peebles, E.D. 2021. Effects of the in ovo injection of VitD3 and 25-hydroxyvitamin D3 in Ross 708 broilers fed commercial or calcium and phosphorus-restricted diets. I. Performance, carcass characteristics, and incidence of woody breast myopathy. Poultry Science. 100:101220. https://doi.org/10.1016/j.psj.2021.101220.
DOI: https://doi.org/10.1016/j.psj.2021.101220

Interpretive Summary: Broilers are commercial chickens reared for meat production. One common issue seen in poultry meat, particularly in breast meat, is called woody breast, whereby the breast meat shows white striations that are often harder than the surrounding meat. The exact cause of woody breast is uncertain. Previous research has investigated the in ovo injection or supplementation of 2 forms of vitamin D (vitamin D3 and 25-hydroxyvitamin D3 (25OHD3) with favorable results found for initial feed conversion ratio and inflammatory response. Thus, the current project further investigated the effects of the in ovo injection of D3 alone or in combination with 25OHD3 on broiler post-hatch performance and meat yield through to processing age while the birds were fed either a commercial diet or a diet restricted in calcium and phosphorous content by 20% for the duration of the trial. In other words, this trial sought to determine if the 2 vitamin D forms given to the chick prior to hatch could help overcome a deficient diet and help alleviate any woody breast in the final meat product. The calcium and phosphorous restricted diet restricted growth of the birds including the breast meat yield in the birds at 41 and 46 days of age and as a result also reduced the incidence of woody breast. At 14 and 40 days of age, the breast meat yield in birds that received an in ovo injection of 25OHD3 alone was higher compared to birds that received the in ovo diluent alone (no vitamin D) or a combination of D3 and 25OHD3. The thought is that the 25OHD3 form of vitamin D may have helped the immune response/inflammatory response of the bird and thus helped with breast meat production. Overall, reducing the growth of the bird helped with woody breast, however, this may not be economically feasible or in the best interest of the bird. The 25OHD3 form of vitamin D continues to be of potential benefit as a supplement given to the commercial broiler before hatch to improve overall production.

Technical Abstract: Effects of the in ovo-injection of vitamin D3 (D3) and 25-hydroxyvitamin D3 (25OHD3) on broiler performance, carcass characteristics, and woody breast myopathy (WBM) incidence were investigated. Live embryonated Ross 708 broiler hatching eggs (2,880) were randomly assigned to one of the following in ovo injection treatments: (1) diluent (50 µL); diluent (50 µL) containing either (2) 2.4 µg D3; (3) 2.4 µg 25OHD3; or (4) 2.4 µg D3 + 2.4 µg 25OHD3. Eggs were injected at 18 d of incubation (doi) using an Inovoject multiegg injector. At hatch, 18 male chicks were randomly placed in each of 6 replicate pens belonging to each in ovo injection and, dietary treatment combination. Birds were fed either a commercial diet or a diet restricted in calcium and phosphorous (ReCaP) content by 20% for the starter, grower and finisher dietary phases. Broiler performance was determined in each dietary phase and breast muscle yield was also determined at 14 and 40 d of age (doa). At 41 and 46 doa, birds were processed for determination of WBM, carcass weight, and the absolute and relative (% of carcass weight) weights of various carcass parts. Compared to birds fed the commercial diet, birds fed ReCaP diets experienced a reduction in performance from 14 to 40 doa, in breast meat yield at 41 and 46 doa, and in WBM at 41 and 46 doa. At 14 and 40 doa, breast meat yield in birds that received an in ovo injection of 25OHD3 alone was higher compared to birds that received diluent alone or a combination of D3 and 25OHD3. Lower WBM incidence in ReCaP-fed birds was associated with a lower breast weight. An increase in breast meat yield in response to 25OHD3 alone may be due to improved immunity and small intestine morphology. However, further study is needed to determine the aforementioned effects.