The present study investigated the use of perforated plastic floors in the rearing of male and female poultry under thermal comfort conditions. The study was conducted in 2 climate chambers, in one was conventional poultry litter (wood shavings) and in the other was a perforated plastic floor. The experimental design was a completely randomized design with the factors wood shavings and plastic floor. In each chamber, the animals were divided into 16 experimental pens (8 with males and 8 with females) with a density of 12 birds/m2. The poultry rearing effect was evaluated in terms of air quality (% concentration of ammonia [NH3] and carbon dioxide [CO2]); broiler performance, e.g., weight gain (kg), feed intake (kg), feed conversion, carcass yield and parts (%), meat production (kg/m2), and viability (% of live birds at d 42); scores of hygiene and mobility; and injuries in the chest, hocks, and footpads. Treatments affected air quality, with higher concentrations of NH3 on d 42 (25 ppm vs. 2 ppm) and CO2 (1,400 ppm vs. 1,000 ppm) for wood shavings than for perforated plastic floor, respectively. Males showed a better performance (weight gain, feed intake and feed conversion) than females on d 42 in both floor types (wood shavings and plastic floor). Males reared on wood shavings showed a higher meet production (35.992 kg/m2) than females (32.257 kg/m2). On the plastic floor, males showed a better viability (100%) than females (94.05%), as well better meet production for males (38.55 kg·m-2) than females (31.64 kg/m2). There was no incidence of breast lesions in any of the studied systems. The birds reared on the plastic floor had better hygiene scores and lower hock injury rates than birds reared in the wood shavings chambers. The results of the present study show that the use of perforated plastic floors in chicken farming is an efficient method, which promotes a better-quality environment, superior production rates, and reduced incidence of injuries.

It is known that the level of dietary protein modulates the enzymatic activity of the digestive tract of fish; however, its effect at the molecular level on these enzymes and the hormones regulating appetite has not been well characterised. The objective of this study was to evaluate the effect of CP on the activity of proteases and the expression of genes related to the ingestion and protein digestion of juveniles of red tilapia (Oreochromis sp.), as well as the effects on performance, protein retention and body composition of tilapia. A total of 240 juveniles (29.32 ± 5.19 g) were used, distributed across 20 tanks of 100 l in a closed recirculation system. The fish were fed to apparent satiety for 42 days using four isoenergetic diets with different CP levels (24%, 30%, 36% and 42%). The results indicate that fish fed the 30% CP diet exhibited a higher growth performance compared to those on the 42% CP diet (P < 0.05). Feed intake in fish fed 24% and 30% CP diets was significantly higher than that in fish fed 36% and 42% CP diets (P < 0.05). A significant elevation of protein retention was observed in fish fed with 24% and 30% CP diets. Fish fed with 24% CP exhibited a significant increase in lipid deposition in the whole body. The diet with 42% CP was associated with the highest expression of pepsinogen and the lowest activity of acid protease (P < 0.05). The expression of hepatopancreatic trypsinogen increased as CP levels in the diet increased (P < 0.05) up to 36%, whereas trypsin activity showed a significant reduction with 42% CP (P < 0.05). The diet with 42% CP was associated with the lowest intestinal chymotrypsinogen expression and the lowest chymotrypsin activity (P < 0.05). α-amylase expression decreased with increasing (P < 0.05) CP levels up to 36%. No significant differences were observed in the expression of procarboxypeptidase, lipase or leptin among all the groups (P > 0.05). In addition, the diet with 42% CP resulted in a decrease (P < 0.05) in the expression of ghrelin and insulin and an increase (P < 0.05) in the expression of cholecystokinin and peptide yy. It is concluded that variation in dietary protein promoted changes in the metabolism of the red tilapia, which was reflected in proteolytic activity and expression of digestion and appetite-regulating genes.

The aim of this study was to evaluate the effect of substitution of Cynodon hay with banana plantation residue hay on the carcass characteristics and tissue composition of commercial cuts of feedlot Santa Inês lambs. Twenty-five whole lambs were used, with an average age of five months and an initial live weight of 26.95 kg (± 1.5), distributed in a completely randomized design with five treatments (1 = 40% Cynodon spp. hay + 60% concentrate; 2 = 20% banana leaf hay + 20% Cynodon spp. hay + 60% concentrate; 3 = 40% banana leaf hay + 60% concentrate; 4 = 20% banana pseudostem hay + 20% Cynodon spp. hay + 60% concentrate; 5 = 40% banana pseudostem hay + 60% concentrate) and five repetitions. The lambs were slaughtered on day 69 of the experiment. The variables evaluated were: live weight without fasting (LWWF), live weight post-fasting (LWPF), morphometric measurements in vivo and postmortem, hot and cold carcass weights (HCW, CCW), hot and cold carcass yield (HCY, CCY), biological performance and weight loss by chilling. The carcasses were divided into eight commercial cuts: neck, shoulder, foreshank and hindshank, breast and flank, loin, leg and rack. The leg, shoulder and loin were dissected into muscle, fat and bone. The animals fed on pseudostem hay showed higher LWWF, LWPF, body length, HCW and CCW; however, the HCY, CCY, morphometric measurements and commercial cut weights and yields were not altered by the treatments. The use of pseudostem hay allows for heavier carcasses; however, the use of coproducts changed the characteristics and carcass yield of the assessed commercial cuts. cinco meses, peso vivo inicial de 26,95 kg (± 1,5), distribuídos em delineamento inteiramente casualizado com cinco tratamentos (1= 40% de feno Cynodon spp. + 60% concentrado, 2= 20% de feno de folha de bananeira e 20% de feno de Cynodon spp. + 60% concentrado, 3= 40% de feno de folha de bananeira + 60% concentrado, 4= 20% de feno de pseudocaule de bananeira e 20% de feno de Cynodon spp. + 60% concentrado, 5= 40% de feno de pseudocaule de bananeira + 60% concentrado) e cinco repetições. Os cordeiros foram abatidos aos 69 dias de experimentação. As variáveis avaliadas foram: peso vivo sem jejum (PVSJ), peso vivo com jejum (PVCJ), medidas morfométricas in vivo e da carcaça, peso da carcaça quente e fria (PCQ, PCF), rendimento da carcaça quente e fria (RCQ, RCF), rendimento biológico e perda por resfriamento. As carcaças foram divididas em oito cortes comerciais, sendo o pernil, paleta e lombos dissecados em músculo, gordura e osso. Os animais alimentados com feno de pseudocaule apresentaram maior PVSJ, PVCJ, comprimento corporal, PCQ, PCF, entretanto, o RCQ, RCF, medidas morfométricas da carcaça, pesos e rendimentos dos cortes comerciais não foram alterados pelos tratamentos. O uso do feno de pseudocaule permite a obtenção de carcaças mais pesadas, entretanto, os coprodutos alteram as características e rendimento da carcaça e dos cortes comerciais avaliados.

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RESUMO Avaliaram-se os efeitos de diferentes níveis de inclusão (0, 100, 200 e 300g kg -1 de MS) de torta de macaúba (TM) na produção leiteira e no comportamento ingestivo de oito vacas Holandesas