Resumo em Inglês:

The purpose of this study was to evaluate the physicochemical and microbiological stability of sausages produced from mechanically separated fish meat (MSM) obtained from Nile tilapia filleting residues. Different heat treatments (pasteurization or smoking) and packaging systems (conventional or vacuum) were used. The sausages were characterized for chemical composition, weight loss, water activity, instrumental texture and sensorial analysis. Additionally, microbiological analysis, instrumental color, pH, thiobarbituric acid reactive substances (TBARS) and total volatile base nitrogen (TVB-N) were assessed during storage. No presence of Escherichia coli, Salmonella sp. or coagulase-positive Staphylococcus was detected; however, the psychrotrophic count in pasteurized sausages exceeded the limits allowed for consumption. pH and lipid oxidation speed (TBARS) values were reduced when vacuum packaging was used. Volatile nitrogenous bases remained virtually constant during the storage period, and higher values were observed in smoked products. Pasteurized sausages remain stable for 10 and 15 days in conventional and vacuum packages, respectively, and smoked sausages remain stable for 25 and 45 days in conventional and vacuum packages, respectively.

Resumo em Inglês:

The objective of this study was to evaluate the effect of photoperiod on locomotor activity, growth and gonadal development in Nile tilapia (Oreochromis niloticus) fingerlings. A completely randomised design was used, with five treatments (0L:24D, 6L:18D, 12L:12D, 18L:6D and 24L:0D) and four replicates, with the aquarium as the experimental unit. One hundred and sixty fingerlings of tilapia weighing 3.21±0.05 g and measuring 4.35±0.07 cm each were distributed among 20 aquaria of 20 L in a recirculation system with the temperature controlled to 27 °C, with eight fish per aquarium. Feeding was carried out twice daily for 75 days, with extruded feed containing 40% crude protein. The fingerlings subjected to a photoperiod of 12L:12D as well as those under 18L:6D and 24L:0D showed the greatest locomotor activity, whereas those under 6L:18D and 0L:24D showed the lowest activity. Fish subjected to a photoperiod of 18L:6D and 24L:0D showed the highest levels of performance. However, manipulation of the photoperiod did not influence the gonadal development, survival or the appearance of deformities in juvenile Nile tilapia. Under long photoperiods (18L:6D and 24L:0D), fish direct their energy to somatic growth and induce best feed efficiency.

Resumo em Inglês:

The present study evaluated the microbial population, fermentation profile, losses and dry matter recovery, and chemical composition of silages of buffel grass at different cutting heights. To evaluate the microbial fermentation dynamics, the treatments resulted from a 4 × 5 factorial combination consisting of 4 cutting heights and 5 fermentation periods, in a completely randomized design with three replications. The fermentation was evaluated at the end of 1, 3, 7, 15 and 30 days. The other characteristics of silages with 30 days were evaluated following a completely randomized design with four treatments, consisting of 4 cutting heights (30, 40, 50 and 60 cm), and five replications. Fermentation period and cutting height effects and interaction between both factors were observed on the populations of lactic acid bacteria (LAB), enterobacteria and molds and yeasts. The peak of development of LAB populations was observed on the seventh day of fermentation for the heights of 40 and 50 cm, with 8.25 and 8.30 log cfu/g, respectively. The pH values of silages ranged with different cutting heights, in which at the height of 50 cm the decrease was most pronounced. However, the pH values were similar between the cutting heights at the end of 30 days of fermentation. Quadratic relationship was observed between lactic acid concentrations and cutting heights. The crude protein content behaved linearly, initially showing 128.5 g/kg DM at 30 cm, decreasing as the cutting heights increased. The neutral detergent fiber and ether extract contents increased linearly with the cutting heights. Based on microbial populations, fermentation, losses and chemical composition, it is recommended to harvest buffel grass for silage from 50 cm on.

Resumo em Inglês:

Data from 2439 goats of the Saanen, Alpine, Anglo Nubian and Toggenburg breeds recorded from 1976 to 2009 by the Association of Goats and Sheep Breeders of Minas Gerais were used in principal component analysis. After consistency of data, six morphological variables (thorax perimeter, body length, withers height, height, width and length of the rump) and 12 variables related to breed standard score and fitness (breed characteristic, head, palette and topline, feet and legs, dairy type, body capacity, udder, rear and front ligament, udder texture, teat and final score) were analyzed. Based on the magnitude of the eigenvalue (lower than 0.7), eleven variables considered redundant were discarded, resulting in reduced costs of technician labor to evaluate the animals. Maintenance of records on height, length, rump width, breed characteristic, dairy type, front ligament and udder texture is recommended.

Resumo em Inglês:

Two experiments were carried out to evaluate, respectively, nitrogen balance (NB) and the productive performance of 31-to-50-day-old rabbits subjected to different levels of lysine and methionine+cystine (met+cys). Seventy-five animals were randomly distributed in 5 × 3 blocks (five levels of lysine: 5.5, 6.5, 7.5, 8.5 and 9.5 g/kg combined with three levels of met+cys: 5.0, 6.0 and 7.0 g/kg), with 15 treatments and five replications for the NB assay. The assay lasted 14 days: 10 days for acclimatization and four days for feces and urine collection. Increasing met+cys levels had a quadratic effect on the nitrogen excreted in urine (NU): the lowest excretion was found at the dietary level of 5.9 g/kg met+cys. Increasing lysine levels also affected NU and nitrogen retained daily (NR): the lowest NU was obtained at the dietary level of 7.28 g/kg lysine, and maximum NR was found at 7.24 g/kg lysine. Increases in met+cys levels in the diets affected neither performance nor carcass characteristics of rabbits up to 50 days of age. On the other hand, body weight at 50 days, daily weight gain and feed conversion of rabbits slaughtered at 50 days had a quadratic effect as the lysine levels increased. The best results were found at 7.5, 7.38 and 7.36 g/kg lysine. Lysine and met+cys levels of 7.4 and 5.0 g/kg in the diet are recommended for 31-to-50-day-old rabbits.

Resumo em Inglês:

This study was conducted to evaluate the effects of digestible lysine levels in diets with and without supplementation of industrial amino acids on performance and fat deposition in the carcass of broilers in the starter phase. One thousand four hundred and forty chickens with initial weight of 168.1±5.0 g were distributed in a completely randomized experimental design, in a 5 × 2 factorial arrangement, composed of five digestible lysine levels (10.0, 11.0, 12.0, 13.0 and 14.0 g/kg) and two types of diet (diet with different proportions of corn and soybean meal and diet supplemented with industrial amino acids to obtain the digestible lysine levels), with eight replications and 18 birds per replication. There was interaction effect only on weight gain and fat deposition in the birds. The lysine levels reduced feed intake linearly in both diets, but caused a linear increase in lysine intake. The lysine levels quadratically affected weight gain and feed conversion, which improved up to the estimated levels of 13.0 and 12.8 g/kg lysine, respectively, when the corn:soybean meal ratio of the diet changed. In the diets supplemented with amino acids, the lysine levels increased weight gain and improved feed conversion linearly. Regardless of the type of diet, protein deposition increased linearly, whereas fat deposition reduced also linearly, as the lysine levels in the diets were increased. The levels of 13.0 and 14.0 g/kg digestible lysine provide, respectively, the best performance in birds fed a diet in which the proportion of corn and soybean meal varies and a diet supplemented with industrial amino acids, in the period from 8 to 21 days of age.

Resumo em Inglês:

Two-hundred sixteen white laying hens were used to assess the ideal ratio of digestible threonine:lysine in diets for laying hens at 24 to 40 weeks of age. Birds were assigned to a randomized block design, with six treatments, six replicates per treatment and six birds per experimental unit. The cage was used as the blocking criterion. Experimental diets contained different digestible threonine:digestible lysine ratios (65, 70, 75, 80, 85 and 90%) with 142 g/kg of crude protein. Experimental diets were formulated to be isonitrogenous and isocaloric with different contents of L-glutamic acid. Feed intake (g/hen/d), egg production (%), egg weight (g), egg mass (g/hen/d), feed conversion ratio (kg/dozen and kg/kg egg), eggshell weight (g), albumen weight (g), yolk weight (g) and body weight gain (g) were assessed. The maximum egg production was observed at 78% digestible threonine:digestible lysine ratio, while the best values of feed conversion ratio (kg/dozen egg) and feed conversion ratio (kg/kg of egg) were observed at 77.6% and 75%, respectively. Feed intake, egg mass and egg contents (yolk, albumen and eggshell) were not affected by treatments. The estimated digestible threonine:digestible lysine ratio of Hy-Line W36 laying hens at 24 to 40 weeks of age is 78%, corresponding to 5.70 g/kg of dietary digestible threonine.

Resumo em Inglês:

Sixty New Zealand rabbits aged 40 days were divided into 4 groups of 15 animals. The control group received a free diet of antibiotic growth promoter (AGP) and inulin. The second group was supplemented with 2.5 g/kg of inulin. The third was administered AGP with 0.1 g/kg of flavomycin. Finally, the fourth group received a 2.5 and 0.1 g/kg inulin/AGP diet. Body weight gain was higher in the control group. Rabbits supplemented with inulin had lower values of triglycerides compared with the control and AGP groups, and their glucose level was significantly lower than those treated with AGP. Additionally, serum calcium and magnesium concentrations were higher than the other groups, particularly with regard to AGP. The bone content with regard to calcium, phosphorus and magnesium in the groups treated with inulin was higher compared with the control; moreover, phosphorus and magnesium were higher than in the AGP group. The thickness of the mucosa and crypt depth in the caecum were significantly higher in rabbits treated with inulin than in the other groups, but especially compared with the AGP group. Also, triglyceride values were lower for rabbits treated with inulin/AGP than for those treated with AGP and the bone magnesium concentration was significantly higher compared with the control group. In addition, inulin was shown to have positive effects on the rabbit, promoting increase in bone and serum calcium, magnesium and phosphorus, decrease in triglyceride levels, and improvement in the caecum (changes in morphology, crypt depth and mucosal thickness).

Resumo em Inglês:

Carcasses of twenty lambs (10 males and 10 females) from the Canaria Hair breed (CHB) and another twenty (10 males and 10 females) from the Canaria breed (CB) of 9.91±0.73 kg and 9.87±0.80 kg live weight, respectively, were studied. In the principal component (PC) analysis, the projection of carcass measurement data in the first PC allowed for clearly distinguishing between CB and CHB. In the analysis of variance, breed effect was observed in the morphology of the carcass: CB lambs showed the longest carcasses and CHB lambs showed the widest carcasses. Due to their wider rump and shorter legs, CHB lambs presented a more compact leg index. The carcasses from Canaria lambs had the highest fat score, the heaviest shoulder and the highest total fat percentage. The carcasses from CHB lambs showed a higher lean percentage. The carcass yield, conformation, degree of fatness and tissue composition were similar in both sexes. However, significant differences in the commercial cut yield were observed: males showed heavier shoulders than females. The effect of sex on carcass quality is unimportant. The breeds are different in important characteristics for the market, such as fatness. This fact is of significant interest because it diversifies the offer and means that different markets can be satisfied.

Resumo em Inglês:

The objective of this study was to evaluate the postweaning history of heifers kept on marandu grass pastures with three canopy heights, in a continuous-grazing system, during the rainy period, on feedlot- or pasture finishing. The effects of three canopy heights (15, 25 and 35 cm) associated with two supplements (mineral salt and protein-energy supplement) and two finishing systems in the dry period (feedlot and open pasture) were studied in the postweaning period during the rainy season. The adopted design was completely randomized, with seven replications (animals) in a 2 × 2 factorial arrangement. The animals which received protein-energy supplement reached the finishing period with greater body weight in relation to those fed mineral salt. In both feedlot and pasture finishing systems, compensatory gain effect was observed in the animals that remained on the low pastures during postweaning compared with the high pastures. This compensatory gain was not verified in the animals that received protein-energy supplement in relation to the mineral salt, and thus the animals were slaughtered beforehand. The heifers on pastures with 25 or 35 cm in height were slaughtered in the same period, and those kept on the low pastures were slaughtered afterwards. The studied factors in the postweaning phase did not affect the carcass characteristics. Animals finished in feedlot slaughtered with the same body weight as those finished on pasture show greater carcass yield, subcutaneous fat deposition and renal pelvic and inguinal fat and greater losses with trimmings for cleaning the main hindquarter meat cuts; however, they provide cuts with the same weight but greater fat cover.