Metabolite profile and consumer sensory acceptability of meat from lean Nellore and Angus × Nellore crossbreed cattle fed soybean oil.

Thirty each Nellore (NEL) and crossbred Angus × Nellore (AxN) were used to evaluate the effect of feeding soybean oil (SBO) and breed on meat sensory acceptability and its relation to muscle metabolite profiles. Cattle were fed for 133 d on two different diets: 1) basal feedlot diet (CON) and 2) CON diet with 3.5% added SBO. No interactions between diet and genetic group were detected for any traits measured. Meat from animals fed SBO diet had lower overall liking, flavor, tenderness and juiciness scores compared to meat from animals fed CON diet. The four most important compounds differing between animals fed CON and SBO diets were betaine, glycerol, fumarate, and carnosine, suggesting that metabolic pathways such as glycerolipid metabolism; glycine, serine and threonine metabolism; glutamine and glutamate metabolism; valine, leucine and isoleucine biosynthesis; and alanine, aspartate and glutamate metabolism were affected by diets. Nellore beef had a higher overall liking and meat flavor scores than AxN beef. The four most important compounds differing between breeds were glycine, glucose, alanine, and carnosine, which may indicate that metabolic pathways such as glutathione metabolism; primary bile acid biosynthesis; alanine, aspartate and glutamate metabolism; and valine, leucine and isoleucine biosynthesis were affected by genetic groups. Meat carnosine, inosine monophosphate, glutamate, betaine, glycerol and creatinine levels were correlated with sensory acceptability scores. Meat metabolite profiles and sensory acceptability were differentially impacted by diet and breed.

Nitrogen metabolism and protein requirements for maintenance of growing Red Norte bulls.

Dietary protein adjustments can reduce environmental impact and economic losses in production systems. However, we lack information regarding nitrogen (N) metabolism and protein requirements for maintenance of crossbred animals such as Red Norte breed, precluding a precise dietary management. The objective was to evaluate the effect of increasing dietary CP levels (9%, 11%, 13%, 15% and 17%) on intake, digestibility and N balance, as well as to estimate the metabolizable protein requirements for maintenance (MPm) of growing Red Norte bulls. Thirty five animals averaging 280 ± 4.0 kg BW were fed during 45 days in a 60 : 40 forage : concentrate ratio diet in which the last 5 days were used for the digestibility trial. Intakes of CP and non-fibrous carbohydrates (NFCs) and feed efficiency linearly increased (P < 0.05) as CP levels increased, while DM, NDF, nitrogen efficiency use and ether extract were not influenced by CP levels (P > 0.05). Digestibilities of DM, organic matter, ether extract, NFC and CP as well as metabolizable energy intake linearly increased (P < 0.05), and true digestibility of CP was not affected (P > 0.05) by treatments. Urinary N and retained N linearly increased (P < 0.05) with the increase in dietary N. The MPm were estimated as 4.46 g/BW0.75 and the efficiency of use of MPm was 0.673. In conclusion, obtained MPm requirements of growing Red Norte bulls are greater than the values reported in literature for Zebu cattle and dietary CP levels of 15% and 17% exhibited great responses for growing Red Norte cattle. However, a cost-benefit evaluation should be done before its use.

Blood parameters of Nellore steers fed a high concentrate diet in two restricted feeding regimes followed by ad libitum feeding / Parâmetros sanguíneos de novilhos Nelore submetidos à dieta de alto concentrado em dois regimes alimentares sequenciais (fase 1: restrição e fase 2: alimento ad libitum)

Blood parameters of 18 Nellore steers submitted to high concentrate diet in two sequential feeding regimes (phase 1: restriction and phase 2: ad libitum feeding) were evaluated. In the first phase, steers were fed for 56 days three intake levels of dry mat-ter (ad libitum, 75 g dry matter (DM)/kg metabolic body weight (BW0.75) or 60 g DM/kg BW(0.75). In the second phase, from the 57th day on feed, animals fed 60 g DM/kg BW(0.75) and 75 g DM/kg BW(0.75) were fed ad libitum until the 136th day. In the 8th, 27th, 55th (first phase), 71st, 84th, 112th and 132nd (second phase) day of experimental period, blood samples were collected and insulin-like growth factor I (IGF-I), triiodothyronine (T3), thyroxine (T4), glucose, plasma ureic nitrogen (PUN) and total protein (TP) were determined. In the first phase IGF-I, T4, glucose and total protein concentration was not different among treat-ments (P>0.05) and there was no interaction between treatment and time (P>0.05). There was an interaction among treatments and time on T3 and plasma ureic nitrogen (P0.05). For plasma ureic nitrogen concentration there was an interaction among treatments and time (P=0.02). Lower levels of diet intake can be used to improve animal performance in feedlot.

Foram avaliados parâmetros sanguíneos de 18 novilhos Nelore submetidos a dois regimes sequenciais de alimentação (fase 1: restrição e fase 2: alimento ad libitum) com dieta de alto teor de concentrado. Na primeira fase, os animais foram alimentados por 56 dias em três níveis de ingestão de matéria seca (MS) representando os tratamentos: ad libitum, 75 g MS/kg peso corporal metabólico (PV0,75) e 60 g MS/kg PV(0,75). Na segunda fase, a partir do 57º dia de confinamento, os animais alimentados com 60 g MS/kg PV(0,75) e 75 g MS/kg PV(0,75) receberam alimentação ad libitum até o 136º dia. No 8º, 27º, 55º, primeira fase, e 71º, 84º, 112º e 132º dia de confinamento, segunda fase, foram colhidas amostras de sangue para determinação das concentrações de fator de crescimento semelhante à insulina I (IGF-I), triiodotironina (T3), tiroxina (T4), glicose, nitrogênio ureico plasmático e proteína total. No período de restrição alimentar as concentrações plasmáticas de IGF-I, T4, glicose e proteína total não foram diferentes entre os tratamentos (P>0,05) e não houve interação entre tratamento e tempo (P>0,05). Foi observada interação entre tratamento e tempo para a concentração plasmática de T3 e nitrogênio ureico no plasma (P0,05). Para a concentração de nitrogênio ureico no plasma houve interação entre os fatores tratamentos e tempo (P=0,02). Níveis mais baixos de ingestão de dieta podem ser usados para melhorar o desempenho animal em confinamento.

Composition of weight gain in Nellore steers at different feed intake levels / Composição do ganho de peso de novilhos Nelore em diferentes níveis de ingestão de alimentos

Thirty six Nellore steers, with an average initial age and weight of 20 months and 360 kg, were fed the same diet in three levels of dry matter intake: ad libitum or in two restriction levels 75g DM/kg BW0.75 or 60g DM/kg BW0.75 during 58 days (Phase 1) to evaluate the effects of feed restriction on weight gain, feed efficiency, diet digestibility, and composition of weight gain in restriction and re-alimentation phases. All steers were fed ad libitum for 78 days (Phase 2). Body composition was estimated with the marker deuterium oxide, which allowed repeated measurements of the same animal and studying its response to re-alimentation. Average daily gain in the restriction phase reflected different weight gain rates provided by feed levels of 0.288 kg, 0.656 kg, and 1.169 kg, respectively for 60g DM/ BW0.75, 75g DM/ BW0.75 and ad libitum. Feed efficiency increased according to feed intake level in Phase 1 and no differences between treatments were observed in Phase 2. Dry matter digestibility did not differ between treatments in both Phase 1 and Phase 2; however, it differed between phases for the same treatment with 78.8% in Phase 1, and with 68.7% in Phase 2 for the treatment with 60 g DM/BW0.75, and 77.8% in Phase 1 and 71.3% in Phase 2 for the treatment with 75 g DM/BW0.75. The deposition of empty weight gain, daily water deposition, ether extract, protein, ash, and energy increased with a higher feed intake level in Phase 1. In Phase 2, no difference occurred between the diet intake levels for empty weight gain, chemical components deposition, and retained energy in the gain. Diet digestibility decreased in Nellore steers fed ad libitum after the period of feed restriction, regardless of the previous restriction level to which the animals were submitted.

Trinta e seis novilhos Nelore, com média de peso e idade inicial de 360 kg e 20 meses, foram alimentados com a mesma dieta em três níveis de ingestão de material seca: à vontade ou em dois níveis de restrição alimentar quantitativa 75g MS/kg PV0,75 ou 60g MS/kg PV0,75 durante 58 dias (Fase 1) para avaliar os efeitos da restrição alimentar no ganho de peso, eficiência alimentar, digestibilidade da dieta e na composição do ganho de peso. Todos os novilhos foram alimentados ad libitum por 78 dias (Fase 2). A composição corporal foi estimada com o marcador óxido de deutério, o qual permite repetir a avaliação no mesmo animal e estudar as respostas à realimentação. O ganho médio diário na fase de restrição alimentar refletiu as diferentes taxas de ganho de peso proporcionadas pelos níveis de alimentação, sendo 0,288 kg, 0,656 kg e 1.169 kg, respectivamente para 60g MS/PV0,75, 75g MS/PV0,75 e ad libitum. A eficiência alimentar variou de acordo com o nível de ingestão de alimentos na Fase 1 e não foram observadas diferenças entre tratamentos na Fase 2. A digestibilidade da matéria seca não diferiu entre tratamentos tanto na Fase 1 como na Fase 2, mas foi diferente entre as Fases para o mesmo tratamento com 78,8% na Fase 1 e 68,7% na Fase 2 para o tratamento 60 g MS/PV0,75 e 77,8% na Fase 1 e 71,3% na Fase 2 para o tratamento 75 g MS/PV0,75. A composição do ganho de peso vazio, a deposição diária de água, extrato etéreo, proteína, cinzas e energia aumentaram de acordo com o nível de ingestão de alimentos na Fase1. Na Fase 2, não houve diferença entre os níveis de ingestão da dieta para ganho de peso vazio, deposição dos componentes químicos e energia retida no ganho. Novilhos Nelore alimentados ad libitum após período de restrição alimentar tiveram a digestibilidade da dieta diminuída, independentemente do...

Composition of weight gain in Nellore steers at different feed intake levels / Composição do ganho de peso de novilhos Nelore em diferentes níveis de ingestão de alimentos

Thirty six Nellore steers, with an average initial age and weight of 20 months and 360 kg, were fed the same diet in three levels of dry matter intake: ad libitum or in two restriction levels 75g DM/kg BW0.75 or 60g DM/kg BW0.75 during 58 days (Phase 1) to evaluate the effects of feed restriction on weight gain, feed efficiency, diet digestibility, and composition of weight gain in restriction and re-alimentation phases. All steers were fed ad libitum for 78 days (Phase 2). Body composition was estimated with the marker deuterium oxide, which allowed repeated measurements of the same animal and studying its response to re-alimentation. Average daily gain in the restriction phase reflected different weight gain rates provided by feed levels of 0.288 kg, 0.656 kg, and 1.169 kg, respectively for 60g DM/ BW0.75, 75g DM/ BW0.75 and ad libitum. Feed efficiency increased according to feed intake level in Phase 1 and no differences between treatments were observed in Phase 2. Dry matter digestibility did not differ between treatments in both Phase 1 and Phase 2; however, it differed between phases for the same treatment with 78.8% in Phase 1, and with 68.7% in Phase 2 for the treatment with 60 g DM/BW0.75, and 77.8% in Phase 1 and 71.3% in Phase 2 for the treatment with 75 g DM/BW0.75. The deposition of empty weight gain, daily water deposition, ether extract, protein, ash, and energy increased with a higher feed intake level in Phase 1. In Phase 2, no difference occurred between the diet intake levels for empty weight gain, chemical components deposition, and retained energy in the gain. Diet digestibility decreased in Nellore steers fed ad libitum after the period of feed restriction, regardless of the previous restriction level to which the animals were submitted.(AU)

Trinta e seis novilhos Nelore, com média de peso e idade inicial de 360 kg e 20 meses, foram alimentados com a mesma dieta em três níveis de ingestão de material seca: à vontade ou em dois níveis de restrição alimentar quantitativa 75g MS/kg PV0,75 ou 60g MS/kg PV0,75 durante 58 dias (Fase 1) para avaliar os efeitos da restrição alimentar no ganho de peso, eficiência alimentar, digestibilidade da dieta e na composição do ganho de peso. Todos os novilhos foram alimentados ad libitum por 78 dias (Fase 2). A composição corporal foi estimada com o marcador óxido de deutério, o qual permite repetir a avaliação no mesmo animal e estudar as respostas à realimentação. O ganho médio diário na fase de restrição alimentar refletiu as diferentes taxas de ganho de peso proporcionadas pelos níveis de alimentação, sendo 0,288 kg, 0,656 kg e 1.169 kg, respectivamente para 60g MS/PV0,75, 75g MS/PV0,75 e ad libitum. A eficiência alimentar variou de acordo com o nível de ingestão de alimentos na Fase 1 e não foram observadas diferenças entre tratamentos na Fase 2. A digestibilidade da matéria seca não diferiu entre tratamentos tanto na Fase 1 como na Fase 2, mas foi diferente entre as Fases para o mesmo tratamento com 78,8% na Fase 1 e 68,7% na Fase 2 para o tratamento 60 g MS/PV0,75 e 77,8% na Fase 1 e 71,3% na Fase 2 para o tratamento 75 g MS/PV0,75. A composição do ganho de peso vazio, a deposição diária de água, extrato etéreo, proteína, cinzas e energia aumentaram de acordo com o nível de ingestão de alimentos na Fase1. Na Fase 2, não houve diferença entre os níveis de ingestão da dieta para ganho de peso vazio, deposição dos componentes químicos e energia retida no ganho. Novilhos Nelore alimentados ad libitum após período de restrição alimentar tiveram a digestibilidade da dieta diminuída, independentemente do...(AU)

Blood parameters of Nellore steers fed a high concentrate diet in two restricted feeding regimes followed by ad libitum feeding / Parâmetros sanguíneos de novilhos Nelore submetidos à dieta de alto concentrado em dois regimes alimentares sequenciais (fase 1: restrição e fase 2: alimento ad libitum)

Blood parameters of 18 Nellore steers submitted to high concentrate diet in two sequential feeding regimes (phase 1: restriction and phase 2: ad libitum feeding) were evaluated. In the first phase, steers were fed for 56 days three intake levels of dry mat-ter (ad libitum, 75 g dry matter (DM)/kg metabolic body weight (BW0.75) or 60 g DM/kg BW(0.75). In the second phase, from the 57th day on feed, animals fed 60 g DM/kg BW(0.75) and 75 g DM/kg BW(0.75) were fed ad libitum until the 136th day. In the 8th, 27th, 55th (first phase), 71st, 84th, 112th and 132nd (second phase) day of experimental period, blood samples were collected and insulin-like growth factor I (IGF-I), triiodothyronine (T3), thyroxine (T4), glucose, plasma ureic nitrogen (PUN) and total protein (TP) were determined. In the first phase IGF-I, T4, glucose and total protein concentration was not different among treat-ments (P>0.05) and there was no interaction between treatment and time (P>0.05). There was an interaction among treatments and time on T3 and plasma ureic nitrogen (P<0.01). In the second phase IGF-I, T3, T4, glucose and total protein concentration was not different among treatments and there was no interaction between treatment and time (P>0.05). For plasma ureic nitrogen concentration there was an interaction among treatments and time (P=0.02). Lower levels of diet intake can be used to improve animal performance in feedlot.(AU)

Foram avaliados parâmetros sanguíneos de 18 novilhos Nelore submetidos a dois regimes sequenciais de alimentação (fase 1: restrição e fase 2: alimento ad libitum) com dieta de alto teor de concentrado. Na primeira fase, os animais foram alimentados por 56 dias em três níveis de ingestão de matéria seca (MS) representando os tratamentos: ad libitum, 75 g MS/kg peso corporal metabólico (PV0,75) e 60 g MS/kg PV(0,75). Na segunda fase, a partir do 57º dia de confinamento, os animais alimentados com 60 g MS/kg PV(0,75) e 75 g MS/kg PV(0,75) receberam alimentação ad libitum até o 136º dia. No 8º, 27º, 55º, primeira fase, e 71º, 84º, 112º e 132º dia de confinamento, segunda fase, foram colhidas amostras de sangue para determinação das concentrações de fator de crescimento semelhante à insulina I (IGF-I), triiodotironina (T3), tiroxina (T4), glicose, nitrogênio ureico plasmático e proteína total. No período de restrição alimentar as concentrações plasmáticas de IGF-I, T4, glicose e proteína total não foram diferentes entre os tratamentos (P>0,05) e não houve interação entre tratamento e tempo (P>0,05). Foi observada interação entre tratamento e tempo para a concentração plasmática de T3 e nitrogênio ureico no plasma (P<0,01). No período de alimento ad libitum as concentrações de IGF-I, T3, T4, glicose e proteína total não foram diferentes entre os tratamentos e não houve interação entre tratamento e tempo (P>0,05). Para a concentração de nitrogênio ureico no plasma houve interação entre os fatores tratamentos e tempo (P=0,02). Níveis mais baixos de ingestão de dieta podem ser usados para melhorar o desempenho animal em confinamento.(AU)