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Baldassini, Welder A. ; Ramirez-Zamudio, German D. ; Duarte, Marcio S. ; Ladeira, Marcio M. ; Pereira, Guilherme L. ; Machado-Neto, Otavio R. ; Torres, Rodrigo N. S. ; de Magistri, Murilo S. ; Camargo, Lucas R. ; Curi, Rogerio A. ; Chardulo, Luis Artur L.

• Tipo de documento: Artigo Científico
• Fonte: JOURNAL OF ANIMAL SCIENCE; v. 103, p. 13-pg., 2025-01-01.

Resumo

This study evaluated the effects of neonatal vitamin A supplementation on intramuscular fat (IMF) deposition and the molecular mechanisms regulating adipogenesis and lipogenesis in Montana x Nellore crossbred beef steers. We hypothesize that neonatal vitamin A supplementation induces long-term transcriptional changes associated with IMF development. Thirty-four calves were randomly assigned to two groups: a control receiving a placebo and a treatment group receiving a single intramuscular injection of 300,000 IU of vitamin A at birth. Longissimus thoracis (LT) muscle samples were collected via biopsy at 40 days of age (cow-calf phase) and again at 400 +/- 10 days of age (finishing phase) immediately after slaughter. At deboning (48 hours postmortem), LT samples were collected between the 12th and 13th ribs for chemical composition assessment. Vitamin A supplementation had no significant effect on weaning weight, average daily gain, final body weight, backfat thickness, or ribeye area (P > 0.05). However, IMF content was significantly higher (P < 0.01) in the vitamin A-supplemented (4.10%) compared to control (2.57%). Transcriptomic analysis revealed 52 and 165 differentially expressed genes (DEGs; FDR < 0.05) during the cow-calf and finishing phases, respectively. Functional enrichment analyses showed that vitamin A supplementation upregulated the actin cytoskeleton, insulin, and calcium signaling pathways during the cow-calf phase, and the PI3K-Akt, AMPK, and PPAR signaling pathways during the finishing phase. Notably, key genes associated with adipogenesis and lipogenesis, such as KRAS, ITGB6, CALML6, CISH, and ATF3 in the cow-calf phase, and LEP, ACACA, FASN, SCD, ELOVL6, and CIDEC in the finishing phase, were upregulated in response to vitamin A, as well as several adipogenic regulators, including PPARG, C/EBPA, and FABP4. Pathway enrichment analysis highlighted the PI3K-Akt signaling pathway as a central mediator of vitamin A's effects on adipocyte differentiation and lipid metabolism. Thus, neonatal vitamin A supplementation can enhance IMF deposition in beef steers by modulating key molecular pathways, without negatively impacting growth performance or carcass traits. (AU)

• Processo FAPESP: 19/14572-2 - Estudo da regulação das vias de sinalização da adipogênese e marmorização da carne de bovinos mestiços Bos taurus-Bos indicus suplementados com vitamina A
• Beneficiário: Luis Artur Loyola Chardulo
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 20/11300-9 - Análise do crescimento muscular, proteólise enzimática postmortem e maciez do músculo L. thoracis de bovinos com diferentes escores de marmorização induzidos pela vitamina A
• Beneficiário: Rayssa Santucci Scapol
• Modalidade de apoio: Bolsas no Brasil - Mestrado
• Processo FAPESP: 23/05002-3 - Utilização de ferramentas ômicas para estudo de características de produção, carcaça e qualidade da carne de bovinos confinados: integração de informações no conceito "from-farm-to-fork"
• Beneficiário: Welder Angelo Baldassini
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 21/07222-5 - Efeito da restrição de vitamina A em dietas de terminação de animais F1 Angus com DEP positiva para marmoreio sobre a expressão gênica e protêomica muscular e os mecanismos envolvidos na deposição de gordura muscular
• Beneficiário: Rodrigo de Nazaré Santos Torres
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado