Resumo No Brasil, circulam informações positivas e negativas sobre o agronegócio. É nesse contexto que a população forma suas atitudes frente ao agronegócio brasileiro. As atitudes estão relacionadas ao conhecimento objetivo, ou seja, as informações científicas acuradas ou dados consolidados que o indivíduo tem em sua memória; e ao conhecimento autoavaliado, ou seja, aquilo que o indivíduo julga saber. O objetivo foi identificar o impacto do conhecimento objetivo e do conhecimento autoavaliado sobre o agronegócio brasileiro nas atitudes da população. Os dados foram coletados por meio da aplicação de questionário com uma amostra de 468 participantes e analisados utilizando estatística descritiva e um modelo de regressão ordinal. Os resultados demonstraram que quanto maior o conhecimento objetivo e quanto maior o conhecimento autoavaliado maior é a probabilidade de um indivíduo ter atitudes positivas frente ao agronegócio. Os resultados também demonstraram que indivíduos com posicionamento político mais a direita tem maior probabilidade de ter atitudes positivas frente ao agronegócio brasileiro.

Abstract In Brazil, positive and negative information is spread about agribusiness. In this context of positive and negative information, the population forms its attitudes towards Brazilian agribusiness. Attitudes are related to objective knowledge, that is, accurate scientific information or consolidated data the individual has in his/her memory, and self-assessed knowledge, that is, what the individual thinks she or he knows. The objective was to identify the impacts of objective knowledge and self-assessed knowledge about Brazilian agribusiness on the population's attitudes. Data were collected through the application of questionnaire to a sample of 468 participants. Data were analyzed using descriptive statistics, and an ordinal logistic regression model. The results show that the greater the objective knowledge and the greater the self-assessed knowledge, the greater the probability of an individual having a more positive attitudes towards Brazilian agribusiness. The results also show that the further to the right on the political spectrum the individual declared himself/herself, the greater the probability of showing more positive attitudes towards the Brazilian agribusiness.

ABSTRACT This study evaluated the behavior of broiler chickens subjected to thermal stress during different periods of the day and age of birds. A total of 180 one-day-old male broiler chicks were allocated to three chambers. Each chamber contained five boxes, with 12 chicks/box. Birds were assigned to a completely randomized design. The birds were filmed, and the images recorded every minute during the two periods: morning (from 08:00 to 09:00 h) and afternoon (from 17:00 to 18:00 h), at 7, 14, and 35 d of age. The frequency of the behavioral category (water intake, feed intake, resting, exploration, and comfort) was determined. Data were subjected to variance analysis for mixed models with rearing temperatures (cold, usual, and hot) and age of birds (7, 14, and 35 d) as subdivided plot, and periods of the day (morning and afternoon) as sub-subdivided plot. Birds at cold and usual temperatures showed higher feed intake than those at hot temperature in the morning. Birds exposed to cold and usual temperatures explored the environment less frequently at 35 d when compared with 14 d. However, chickens at hot temperature showed decreased exploration according to the increase of age. Birds spent more time feeding during the morning, regardless of age and rearing temperature. Also, during this period of the day, chickens spent most of the time exploring the environment. The frequency of feed intake and exploration decreases with the increase of age. The similarity of behavior between chickens reared at cold and usual temperatures may be due to a change in the thermal comfort zone of the birds. It suggests that the real thermal comfort temperature is between the two temperature ranges studied (cold and usual).

ABSTRACT The effect of additives used in the feed of broilers on anaerobic bio-digestion of poultry litter was evaluated. Four diets were used: NC: negative control; DFM: NC + 500 ppm direct-fed microbials (DFM) containing Bacillus subtilis and Bacillus licheniformis; ENZ: diet formulated with an enzyme blend (20 ppm phytase, 200 ppm protease and 200 ppm xylanase); DFM+E: ENZ + DFM. Substrates for the anaerobic bio-digestion were prepared with litter from each treatment, containing 4 % total solids (TS). These were used in 16 continuous bio-digesters with a 2 kg d−1 load, to determine the production and potential biogas production and composition during an 85-day period. Influent and effluent samples were collected for the amounts of TS and volatile solids (VS), fiber fraction (neutral detergent fiber [NDF], acid detergent fiber [ADF] and lignin), nutrients (N, P and K), and total and thermotolerant coliforms to be determined. For all treatments a reduction in the following effluents was observed as follows: TS (49, 48, 48 and 50 %) VS (70, 54, 55 and 62 %) NDF (91, 90, 95 and 96 %) ADF (89, 88, 93 and 94 %) and lignin (80, 76, 89 and 88 %). The efficiency of the treatment for coliforms in bio-digesters was higher than 90 % in the 85-day period in all treatment groups. There was a reduction in biogas and methane production when DFM (5500 and 4000 mL) and DFM + E (5800 and 4100 mL) were used, compared to treatments NC (6300 mL and 4400) and ENZ (6400 and 4500 mL). The potential production of reduced TS and VS was higher in ENZ (1:00 and 1.74 106 mL kg−1) when compared to NC (0.88 and 1:02 106 mL kg−1), DFM (0.80 and 1:40 106 mL kg−1) and DFM + E (0.88 1:25 and 106 mL kg−1). The additives did not affect the percentage of methane production, and all treatments showed values higher than 70 %. Adding enzymes to the diet of broilers influences the litter characteristics and, as a consequence, increases biogas production. The addition of DFM and DFM + E to broiler diets reduced biogas and methane production.