RESUMO
This experiment was designed to evaluate the effects of lipid source and fatty acid (FA) profile on intake, performance, carcass characteristics, expression of enzymes, and sensorial analysis of Bos indicus animals offered a high-concentrate diet. On day 0, 96 noncastrated animals were blocked by initial body weight (400 ± 19.3 kg), randomly allocated to 1 of 24 pens (4 animals/pen), and pens were randomly assigned to receive: 1) control: basal diet composed of whole cottonseed and corn germ as lipid substrates (CONT; n = 6), 2) calcium salts of fatty acids (CSFA) of soybean: CSFA of soybean oil as replacement for whole cottonseed and corn germ (calcium salts of soybean oil [CSSO]; n = 6), 3) CSFA-Blend: CSFA of palm, cottonseed, and soybean oil as replacement for whole cottonseed and corn germ (calcium salts of vegetable oils [CSVO]; n = 6), and 4) Mix: basal diet containing whole cottonseed, corn germ, and CSVO (MIXT; n = 6). Experiment lasted 108 d and performance, ultrasound measurements, as well as carcass characteristics were evaluated. Additionally, meat FA profile, expression of enzymes involved in lipid metabolism, and sensorial analysis were evaluated. No treatment effects were observed on performance variables, ultrasound, and carcass traits (P ≥ 0.22), whereas animals receiving CONT had a greater intake of C10:0, C16:0, C16:1 trans-9, C18:1 cis-9, C18:2, C18:3, total FA, monounsatured FA (MUFA), and polyunsaturated FA (PUFA) vs. CSSO and MIXT (P < 0.05). Conversely, intake ratios of saturated FA (SFA):MUFA and SFA:PUFA were all reduced for CONT vs. other treatments. Meat obtained from CONT animals had greater colorimetric (L*, a*, and b*) values vs. MIXT (P < 0.01). On meat FA profile, CONT increased C18:0 vs. supplementation with calcium salts (P < 0.02) and supplementation with CSSO yielded greater meat concentrations of C18:1 trans-10 and C18:2 CLA intermediates (P < 0.01). Expression of SREBP-1, SCD, and LPL was downregulated for CSSO (P < 0.05). For sensorial analysis, regular flavor was greater (P = 0.01) for CSSO vs. other treatments, but also greater aroma (P = 0.05) vs. CONT and CSVO. In summary, addition of different lipid sources with varying FA profiles into high-concentrate diets did not affect performance and carcass characteristics of B. indicus animals, but supplementation with calcium salts of soybean oil inhibited the mRNA expression of enzymes involved in lipid metabolism, whereas flavor and aroma were positively affected by this lipid source.
RESUMO
O objetivo do presente estudo foi avaliar o desempenho e características de carcaça de bovinos Nelore castrados e não castrados terminados em confinamento com dieta de alto concentrado. Trinta e seis bovinos machos da raça Nelore com idade de 24 meses, provenientes de recria em sistema de pastejo contínuo, foram divididos em dois grupos de 18 animais (castrados e não castrados) com peso vivo inicial (PVi) médio de 347,5 kg ± 21,61 kg. O delineamento experimental foi em blocos casualizados, divididos de acordo com o PVi para cada condição sexual avaliada, constituindo desta forma dois tratamentos experimentais: animais castrados e animais não castrados. Cada tratamento foi composto por seis baias (3 animais/baia), sendo estas consideradas as unidades experimentais do estudo. O período de confinamento foi de 112 dias, sendo o abate realizado no 113º dia. Foram avaliados a ingestão de matéria seca (IMS), o ganho de peso diário (GPD), conversão alimentar (CA) e eficiência alimentar (EA). Além disso, foram avaliados a deposição de tecido muscular e adiposo por meio de ultrassonografia. Após o abate dos animais foram determinados o peso de carcaça quente (PCQ), o peso de carcaça fria (PCF) e rendimento de carcaça (RC). Os dados foram analisados utilizando-se o programa PROC MIXED do SAS e teste de Tukey (P ≤ 5%). Não houveram diferenças significativas para as variáveis PVi e IMS em porcentagem de PV. Já as variáveis PVf, GPD, CA e EA apresentaram efeitos significativos, tendo o grupo de animais não castrados melhor desempenho produtivo. Para as avaliações de características de carcaça foram observadas diferenças significativas para PCQ e PCF onde os animais do grupo não castrado também apresentaram melhores pesos de carcaça. Portanto, conclui-se que para sistemas de confinamento com dietas de alto teor de concentrado, a castração de bovinos Nelore não é recomendada, pois interferiu negativamente no desempenho produtivo das carcaças dos animais castrados.(AU)
The objective of the present study was to evaluate the performance and carcass characteristics of Nelore bulls and steers, finished in feedlot with high concentrate diet. Thirty-six male Nelore cattle with 24 months old, from rearing in a continuous grazing system were divided into two groups of 18 animals (castrated and non-castrated) with initial mean body weight (iBW) of 347.5 kg ± 21.61 kg. The experimental design was a randomized complete block according to iBW for each sexual condition evaluated, constituting two experimental treatments: castrated animals and non-castrated animals. Each treatment consisted of six pens (3 animals/pen), these being considered the experimental units. The feedlot period was 112-days and the slaughter was carried out on the 113th day. The dry matter intake (DMI), average daily gain (ADG), feed conversion (F:G) and feed efficiency (G:F) were evaluated. In addition, the deposition of muscular and adipose tissue was evaluated by means of ultrasonography. After slaughtering of the animals the hot carcass weight (HCW), cold carcass weight (CCW) and carcass yield (YG) were determined. The data were analyzed using thePROC MIXED program from SAS and Tukey test (P ≤ 5%). There was no significant difference for the variables iBW and DMI in percentage of BW. The fBW, ADG, F:G and G:F variables had significant effects, and the group of non-castrated animals obtained abetter productive performance. For the carcass traits evaluations, a significant difference was observed for HCW and CCW, where animals from the non-castrated group also had better carcass data. Therefore, it is concluded that for feedlot systems with highconcentrate diets, castration of Nellore cattle is not recommended because it interfered negatively in the productive performance of the castrated animals.(AU)
Assuntos
Animais , Masculino , Bovinos , Castração/veterinária , Aumento de Peso , Ração Animal , Espaços ConfinadosRESUMO
O objetivo do presente estudo foi avaliar o desempenho e características de carcaça de bovinos Nelore castrados e não castrados terminados em confinamento com dieta de alto concentrado. Trinta e seis bovinos machos da raça Nelore com idade de 24 meses, provenientes de recria em sistema de pastejo contínuo, foram divididos em dois grupos de 18 animais (castrados e não castrados) com peso vivo inicial (PVi) médio de 347,5 kg ± 21,61 kg. O delineamento experimental foi em blocos casualizados, divididos de acordo com o PVi para cada condição sexual avaliada, constituindo desta forma dois tratamentos experimentais: animais castrados e animais não castrados. Cada tratamento foi composto por seis baias (3 animais/baia), sendo estas consideradas as unidades experimentais do estudo. O período de confinamento foi de 112 dias, sendo o abate realizado no 113º dia. Foram avaliados a ingestão de matéria seca (IMS), o ganho de peso diário (GPD), conversão alimentar (CA) e eficiência alimentar (EA). Além disso, foram avaliados a deposição de tecido muscular e adiposo por meio de ultrassonografia. Após o abate dos animais foram determinados o peso de carcaça quente (PCQ), o peso de carcaça fria (PCF) e rendimento de carcaça (RC). Os dados foram analisados utilizando-se o programa PROC MIXED do SAS e teste de Tukey (P ≤ 5%). Não houveram diferenças significativas para as variáveis PVi e IMS em porcentagem de PV. Já as variáveis PVf, GPD, CA e EA apresentaram efeitos significativos, tendo o grupo de animais não castrados melhor desempenho produtivo. Para as avaliações de características de carcaça foram observadas diferenças significativas para PCQ e PCF onde os animais do grupo não castrado também apresentaram melhores pesos de carcaça. Portanto, conclui-se que para sistemas de confinamento com dietas de alto teor de concentrado, a castração de bovinos Nelore não é recomendada, pois interferiu negativamente no desempenho produtivo das carcaças dos animais castrados.
The objective of the present study was to evaluate the performance and carcass characteristics of Nelore bulls and steers, finished in feedlot with high concentrate diet. Thirty-six male Nelore cattle with 24 months old, from rearing in a continuous grazing system were divided into two groups of 18 animals (castrated and non-castrated) with initial mean body weight (iBW) of 347.5 kg ± 21.61 kg. The experimental design was a randomized complete block according to iBW for each sexual condition evaluated, constituting two experimental treatments: castrated animals and non-castrated animals. Each treatment consisted of six pens (3 animals/pen), these being considered the experimental units. The feedlot period was 112-days and the slaughter was carried out on the 113th day. The dry matter intake (DMI), average daily gain (ADG), feed conversion (F:G) and feed efficiency (G:F) were evaluated. In addition, the deposition of muscular and adipose tissue was evaluated by means of ultrasonography. After slaughtering of the animals the hot carcass weight (HCW), cold carcass weight (CCW) and carcass yield (YG) were determined. The data were analyzed using thePROC MIXED program from SAS and Tukey test (P ≤ 5%). There was no significant difference for the variables iBW and DMI in percentage of BW. The fBW, ADG, F:G and G:F variables had significant effects, and the group of non-castrated animals obtained abetter productive performance. For the carcass traits evaluations, a significant difference was observed for HCW and CCW, where animals from the non-castrated group also had better carcass data. Therefore, it is concluded that for feedlot systems with highconcentrate diets, castration of Nellore cattle is not recommended because it interfered negatively in the productive performance of the castrated animals.