Feedlot diets containing different starch levels and additives change the cecal proteome involved in cattle's energy metabolism and inflammatory response.

Diets for feedlot cattle must be a higher energy density, entailing high fermentable carbohydrate content. Feed additives are needed to reduce possible metabolic disorders. This study aimed to analyze the post-rumen effects of different levels of starch (25%, 35%, and 45%) and additives (monensin or a blend of essential oils and exogenous α-amylase) in diets for Nellore feedlot cattle. The cecum tissue proteome was analyzed via two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and then differentially expressed protein spots were identified with liquid chromatography-tandem mass spectrometry (LC-MS/MS). The use of blends of essential oils associated with α-amylase as a feed additive promoted the upregulation of enzymes such as triosephosphate isomerase, phosphoglycerate mutase, alpha-enolase, beta-enolase, fructose-bisphosphate aldolase, pyruvate kinase, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), L-lactate dehydrogenase B, L-lactate dehydrogenase A chain, L-lactate dehydrogenase, and ATP synthase subunit beta, which promote the degradation of carbohydrates in the glycolysis and gluconeogenesis pathways and oxidative phosphorylation, support pyruvate metabolism through the synthesis of lactate from pyruvate, and participate in the electron transport chain, producing ATP from ADP in the presence of a proton gradient across the membrane. The absence of proteins related to inflammation processes (leukocyte elastase inhibitors) in the cecum tissues of animals fed essential oils and amylase may be because feed enzymes can remain active in the intestine and aid in the digestion of nutrients that escape rumen fermentation; conversely, the effect of monensin is more evident in the rumen and less than 10% results in post-ruminal action, corroborating the hypothesis that ionophore antibiotics have a limited effect on the microbiota and intestinal fermentation of ruminants. However, the increase in starch in these diets promoted a downregulation of enzymes linked to carbohydrate degradation, probably caused by damage to the cecum epithelium due to increased responses linked to inflammatory injuries.

Growth performance and rumen morphometrics of Nellore and ½ Angus/Nellore feedlot cattle adapted over 9 and 14 days to high-concentrate diets.

The objective of this study was to evaluate the effects of adapting Nellore and ½ Angus/Nellore (AN) feedlot cattle over periods of 9 and 14 days to high-concentrate diets on performance, feeding behaviour, carcass traits and rumen morphometrics. Seventy-two yearling bulls (313.5 kg ± 24.5), 36 Nellore and 36 AN, were randomly allocated in 24 pens (3 animals/pen; 24 m2 and 2.0 m of bunk space/animal) according to a randomized complete block design with a 2 × 2 factorial arrangement of treatments as follows: Nellore adapted for 9 days, Nellore adapted for 14 days, AN adapted for 9 days, and AN adapted for 14 days. Each treatment was composed by 6 pens (considered the experimental unit in this study). The adaptation lasted either 9 or 14 days and consisted of 3 step-up diets. Therefore, yearling bulls received the finishing diet containing 86% concentrate either on day 10 or 15 of the study, which lasted 89 days taking into account adaptation and finishing periods. Cattle were slaughtered in a commercial abattoir, and two 1-cm2 -rumen fragments, one from cranial and another from ventral sac, were collected. The AN cattle outperformed Nellore in terms of average daily gain (1.71 kg/day vs. 1.27 kg/day, p < 0.01), gain:feed ratio (0.137 kg/kg vs. 0.127 kg/kg, p = 0.02) and hot carcass weight (243.64 kg vs. 228.98 kg, p < 0.01). No main effect of the adaptation period was observed for any of the feedlot performance and carcass traits variables evaluated. Compared to feedlot cattle adapted for 9 days, feedlot cattle adapted for 14 days sorted against long (0.68 vs. 0.91, p < 0.01) and for fine particles (1.04 vs. 1.00, p = 0.01). An interaction (p < 0.01) of genotype and adaptation period was observed for rumenitis, where Nellore bulls adapted for 14 days presented the highest scores. In conclusion, there was no evidence that either Nellore or AN cattle benefit from an adaptation period shorter than 14 days.

Evaluation of liquid and powdered forms of polyclonal antibody preparation against Streptococcus bovis and Fusobacterium necrophorum in cattle adapted or not adapted to highly fermentable carbohydrate diets.

OBJECTIVE: Feed additives that modify rumen fermentation can be used to prevent metabolic disturbances such as acidosis and optimize beef cattle production. The study evaluated the effects of liquid and powdered forms of polyclonal antibody preparation (PAP) against Streptococcus bovis and Fusobacterium necrophorum on rumen fermentation parameters in ruminally cannulated non-lactating dairy cows that were adapted or unadapted to a high concentrate diet. METHODS: A double 3×3 Latin square design was used with three PAP treatments (control, powdered, and liquid PAP) and two adaptation protocols (adapted, unadapted; applied to the square). Adapted animals were transitioned for 2 weeks from an all-forage to an 80% concentrate diet, while unadapted animals were switched abruptly. RESULTS: Interactions between sampling time and adaptation were observed; 12 h after feeding, the adapted group had lower ruminal pH and greater total short chain fatty acid concentrations than the unadapted group, while the opposite was observed after 24 h. Acetate:propionate ratio, molar proportion of butyrate and ammonia nitrogen concentration were generally greater in adapted than unadapted cattle up to 36 h after feeding. Adaptation promoted 3.5 times the number of Entodinium protozoa but copy numbers of Streptococcus bovis and Fibrobacter succinogens genes in rumen fluid were not affected. However, neither liquid nor powdered forms of PAP altered rumen acidosis variables in adapted or unadapted animals. CONCLUSION: Adaptation of cattle to highly fermentable carbohydrate diets promoted a more stable ruminal environment, but PAP was not effective in this study in which no animal experienced acute or sub-acute rumen acidosis.

Anticorpos policlonais em dietas com alta inclusão de concentrado para bovinos confinados / Polyclonal antibodies for feedlot cattle fed high-concentrate diets

Dentre as alternativas para substituir o uso de ionóforos classificados como antibiótico por alguns comitês, a utilização de anticorpos policlonais classificados como promotores de crescimento naturais tem se mostrado alternativa interessante e economicamente eficiente. Recentes estudos demonstraram pontos positivos na utilização desse aditivo em dietas com alta inclusão de ingredientes concentrados para bovinos confinados, traduzido por melhora de desempenho e saúde ruminal, em alguns casos, semelhantes à monensina sódica. No entanto, alguns pontos dessa nova tecnologia ainda devem ser elucidados, entre eles, a possível perda de atividade da forma sólida de apresentação do preparado e a diminuição do rendimento de carcaça encontrado em alguns estudos. Contudo, a presente revisão destaca a possibilidade de substituição da monensina sódica por anticorpos policlonais sem resultar em diminuição de desempenho e de rentabilidade para a bovinocultura de corte brasileira.

Among alternatives to replace ionophores, which are classified as antibiotics by some committees, the feeding of polyclonal antibodies have shown an interesting and economically efficient alternative. Recent studies have demonstrated some advantages of adding polyclonal antibodies into high-concentrate diets for feedlot cattle, showed by increased performance and ruminal health, in some cases similar to sodium monensin. However, there are blind spots of this innovated technology that still need to be elucidated, as example, if the dry form of the preparation is inactivated and decreased carcass-dressing percentage. All in all, this review demonstrates the possibility of replacing sodium monensin by this feed additive without negatively impacting animal performance and profit of cattle feeders in Brazil.

Características bioquímicas da carne de bubalinos Mediterrâneo terminados em confinamento e abatidos em diferentes pesos / Biochemicals meat traits from Mediterranean buffaloes finished in feedlot and slaughtered at different weights

Este trabalho teve como objetivo avaliar as características bioquímicas da carne de bubalinos Mediterrâneo terminados em confinamento e abatidos em diferentes pesos. Foram utilizados 28 bubalinos Mediterrâneo jovens, com idade de 9 meses, e peso vivo médio inicial de 240kg. Os animais foram alimentados com ração total à vontade em regime de confinamento até atingirem pesos de abate de 450, 480, 510 e 540kg de peso vivo (tratamentos). Os valores de pH e temperatura dos músculos Longissimus dorsi e Bíceps femoris foram coletados a intervalos de duas horas durante 24 horas após o abate. Determinou-se a cor da carne pelos métodos subjetivo e objetivo. Não houve efeito de interação entre tratamento e tempo de coleta. Não houve diferença significativa entre os tratamentos em relação ao pH e à temperatura nos dois músculos estudados (Longissimus dorsi e Bíceps femoris) durante o processo de resfriamento das carcaças. Os valores médios de pH inicial e pH final dos músculos Longissimus dorsi e Bíceps femoris foram de 6,6 e 5,4; e de 6,3 e 5,5, respectivamente. Os valores médios de temperatura inicial e final dos músculos Longissimus dorsi e Bíceps femoris foram 39,7°C e 4,1°C; 40,4°C e 7,0°C, respectivamente. Quanto à cor da carne, pelo método subjetivo, não houve diferença significativa entre os tratamentos estudados, obtendo-se a média geral de 3,41 pontos. Em relação à cor da carne pelo método objetivo, não houve diferença significativa entre os tratamentos estudados. Os valores médios encontrados foram : L*= 35,16; a*=12,43 e b*=5,29. A carne bubalina, apesar de se apresentar mais escura que a carne bovina, não traz prejuízos quanto ao aspecto visual para o consumidor.

This work was aimed at evaluating the biochemical meat traits from Mediterranean buffaloes finished in feelot and slaughtered at different weights. Twenty eight Mediterranean young buffaloes, averaging 240kg initial live weight and nine months of age, were used. The animals were full fed with total mixed ration in feedlot until reaching slaughter weights of 450, 480, 510 and 540kg live weight (treatments). The pH values and temperature of the Longissimus dorsi and Biceps femoris muscles were collected at 2 hours intervals during 24 hours after the slaughter. Meat color was determined through the subjective and objective methods. No interaction effect was observed between treatment and time of ph and temperature collection. No treatment effects was observed in relation to the pH and temperature in the two studied muscles (Longissimus dorsi and Biceps femoris) during the cooling carcass process. The average values of initial pH and ultimatel pH of Longissimus dorsi and Biceps femoris muscles were 6.6 and 5.4; 6.3 and 5.5, respectively. The average values of initial and ultimate temperature of Longissimus dorsi and Biceps femoris muscles, were 39.7°C and 4.1°C; 40.4°C and 7.0°C, respectively. Meat color by the subjective method, did not differ among treatments studied, with general average of 3.41 points. Meat color obtained by the objective method, did not differ among the treatments studied, with average values: L * = 35.16; a*=12.43 and b*=5.29. In spite of presenting darker than bovine meat, buffalo meat doesn't bring damages as for the visual aspect for the consumer.