ABSTRACT For every 10 liters of milk, approximately one kilogram of cheese is obtained, and the rest is whey; the whey is rich in proteins, carbohydrates, and minerals and is usually discarded, causing contamination problems due to its high content of organic matter. Whey from a cheese manufacturer in Tlaxcala was ultra-filtered, obtaining a concentrated whey with 7.79 % proteins; the latter was then spray-dried, obtaining concentrated whey powder with 47 % protein; both products comply with the minimum protein indicated in the CXS 289-1995 standard (11 %), so they can be directly marketed or used for reprocessing. The average yield of Oaxaca cheese adding between 5 and 8 % of concentrated whey was 11.33 %, and with no concentrated whey was 11.41 %; in both cases, the consistency of the cheese was similar between them. It was also found that by adding 0.5 % concentrated whey powder to the cheese-making process, the yield increased by 4.16 % compared to the use of 1 % milk powder. By ultra-filtering the whey and drying the resulting fractions, products obtained that can be marketed by the company, in addition to being used in the production of Oaxaca cheese, which implies an economic benefit for the company. In addition to the environmental advantages due to the decrease in contamination due to the disposal of whey.

RESUMEN Por cada 10 litros de leche se obtiene aproximadamente un kilo de queso, el resto es lactosuero; éste último es rico en proteínas, carbohidratos y minerales y usualmente se desecha, ocasionando problemas de contaminación por su alto contenido de materia orgánica. El lactosuero de un fabricante de quesos en Tlaxcala se ultrafiltró, se obtuvo un lactosuero concentrado con 7.79 % de proteínas; este último se secó por aspersión obteniéndose el lactosuero concentrado en polvo con 47 % de proteínas; ambos productos cumplen con el mínimo de proteína indicado en la norma CXS 289-1995 (11 %), por lo que se pueden comercializar directamente o ser utilizado para reprocesamiento. Al agregar máximo 8 % de lactosuero concentrado para la elaboración de queso Oaxaca, se obtuvo un rendimiento promedio de 11.33 %, sin lactosuero el rendimiento fue de 11.46 %; en ambos casos la consistencia del queso obtenido fue similar entre ellos. También se encontró que al agregar 0.5 % de lactosuero concentrado en polvo al proceso de elaboración del queso, el rendimiento subió 4.16 % comparado con el uso de 1 % de leche en polvo. Al ultrafiltrar el lactosuero y secar las fracciones resultantes se obtienen productos que puede comercializar la empresa, además que se pueden emplear en la elaboración de queso Oaxaca, lo que implica un beneficio económico a la empresa. Además de las ventajas ambientales por la disminución en la contaminación por el desechado del lactosuero.

RESUMO Foram alojados 640 pintainhos de corte, sendo metade de machos e metade de fêmeas, da linhagem Cobb, de um a 49 dias de idade. Foi adotado um delineamento inteiramente ao acaso, em esquema fatorial 2 × 4. Os tratamentos experimentais consistiram em quatro níveis de suplementação de zinco orgânico e um controle inorgânico, e diferentes sexos, com quatro repetições de 16 aves por parcela experimental. Foram avaliados o desempenho, a característica da carcaça e dos cortes, bem como a qualidade de carne dos frangos. O aumento dos níveis de zinco elevou o consumo de ração dos frangos. Os frangos que receberam zinco orgânico na exigência mínima apresentaram melhor conversão alimentar comparados àqueles que receberam ração de fonte inorgânica. O aumento nos níveis de zinco orgânico proporcionou redução no teor de gordura abdominal para fêmeas, mas níveis de zinco orgânico prejudicaram a estabilidade oxidativa da carne. Conclui-se que frangos machos apresentam melhor desempenho, carcaça e qualidade de carne em relação às fêmeas, e que o zinco orgânico melhora a conversão alimentar dos frangos, reduz a gordura abdominal, porém eleva a oxidação lipídica da carne.

ABSTRACT A total of 640 one-day-old Cobb broiler chicks, half male and half female, were reared up to 49 days of age. A completely randomized 2 × 4 factorial design was used. Experimental treatments consisted of four levels of organic zinc supplementation and one control (inorganic zinc supplementation) and two levels of sex (female and male), with four replicates of 16 birds per experimental plot. Animal performance, carcass and cut yields, and meat quality were evaluated. Feed intake increased with zinc supplementation. Broilers that received the lowest level of organic zinc showed better feed conversion than those fed an equivalent level of inorganic zinc. Increased levels of organic zinc reduced the abdominal fat content in females but impaired the oxidative stability of meat. The results showed that male broilers have better performance, carcass yield, and meat quality than females and that organic zinc improves broiler feed conversion and reduces abdominal fat but increases lipid oxidation in meat.

RESUMO A adição de óleos na dieta de frangos de corte proporciona muitas vantagens, visto que, dependendo do perfil de ácidos graxos, pode melhorar o desempenho e atuar como estimulante do sistema imune. Assim, este estudo teve como objetivo avaliar as características produtivas, o rendimento de carcaça, os cortes e a resposta imune humoral de frangos de corte alimentados com diferentes fontes de óleos e vitamina E. Foram utilizados 312 pintainhos de corte machos da linhagem Cobb com um dia de idade, distribuídos em delineamento inteiramente ao acaso, com oito repetições compostas de 13 aves por parcela experimental. Os tratamentos experimentais consistiram em óleo de soja, óleo de canola e óleo de canola mais adição de vitamina E. As variáveis analisadas foram ganho de peso, consumo de ração, conversão alimentar, rendimento de carcaça, cortes comerciais e resposta imune humoral. Os resultados obtidos mostram que houve diferença significativa no desempenho somente na fase pré-inicial, quando as aves que receberam o tratamento com óleo de canola e vitamina E apresentaram piores ganhos de peso. Não foram observadas diferenças significativas para as outras variáveis analisadas. Conclui-se que a utilização de diferentes fontes lipídicas associadas ou não à vitamina E não afeta as características produtivas de carcaça, cortes e resposta imune humoral em frangos de corte em relação ao uso de óleo de soja.

ABSTRACT Oil inclusion in poultry diets provides many advantages and according to the fatty acid profile it is possible to achieve performance improvement as well as immune system stimulation. Thus, the study aimed to evaluate productive performance, carcass and cuts yields and also the humoral immune response of broilers consuming diets formulated with different oil sources and vitamin E. A total of 312 one-day old male Cobb was distributed, in a completely randomized design, in three treatments with eight replications of 13 birds. The experimental treatments were the diets that had different oil source as follows: soybean oil, canola oil and canola oils with vitamin E. The analyzed parameters were weight gain, feed intake, feed conversion ratio, carcass and cut yields and humoral immune response. For the treatment with canola oil and vitamin E a reduction on weight gain during the pre-starter stage was observed. For the other evaluated parameters, no significant differences were observed. In conclusion, the use of canola oil or canola oil with added vitamin E does not affect the productive performance, carcass and cut yields and humoral immune response in broiler chicken in relation soybean oil use.

ABSTRACT Griller-type chickens are broilers slaughtered between27and 29 days old weighing 1.3 to 1.5 kg and sold as a whole carcasses. The aim of the present study was to evaluate the growth performance, carcass traits, and meat quality of female broilers of four genetic lines reared for the production of griller-type chickens. A total of 960 broiler chicks was allotted in a randomized block design with four treatments and eight replicates of 30 birds per experimental plot. Each experimental treatment consisted of four different commercial lines, identified as A, B, C and D. The analyzed parameters were weight gain, feed intake, feed conversion ratio, livability, production efficiency index, carcass and cut yields, and meat quality according to breast meat color (L*, a*, b*), water-holding capacity (WHC), cooking losses, and shear force. Weight gain, feed intake, feed conversion ratio, and livability were different (p<0.05) among the lines; however, no differences were observed for the production efficiency index. Results show that lines presented similar performance; however, lines A, B, and C had a better carcass and breast yield, and line A, the best meat quality. Therefore, line A would be the most suitable for the production of griller-type chickens.

The aim of this paper was to analyze the myofiber characteristics of four distinct genetic pork groups and correlate them with the meat quality. 46 animals (23 barrows and 23 females) from four genetic lines were used, representing the experimental treatments: high-lean commercial cross-bred line; commercial cross-bred line selected for ends of prolificacy, non selected genetic line and crossbred animals (Landrace x Large White). Were analyzed the sarcomere length, myofiber differentiation, myofiber number and diameter and meat quality (colour, marbling and dripping loss). It was used a complete randomized design with a 4x2 factorial arrangement (4 genetic lines and 2 sexes). The high-lean commercial cross-bred line, commercial cross-bred line selected for ends of prolificacy and Landrace x Large White animals presented greater myofiber number than non selected animals (p<0.05). Landrace x Large White animals presented the greatest cell diameter and non selected animals and commercial cross-bred line selected for ends of prolificacy animals presented the smallest averages for this trait (p<0.05). There were no differences among genetic lines for sarcomere length. The commercial cross-bred line selected for ends of prolificacy animals had less glicolitic fibers percentage and more intermediate fiber percentage (p<0.05) than the other genetic groups. The high-lean commercial cross-bred line and commercial cross-bred line selected for ends of prolificacy had the greatest (p<0.05) and the smallest (p<0.05) dripping loss values, respectively. Non selected animals presented the greatest marbling value and the darkest meat (p<0.05), while they showed more intramuscular-fat than high-lean commercial cross-bred line animals (p<0.05) and showed the darker meat (p<0.05). Barrows presented lighter paler meat than females. The correlation analysis indicates that the myofiber number was positively associated with dripping loss values and lightness. It also indicates that muscle with greater glicolitic fiber present greater marbling value. In this way we conclude that the myofiber number and type are related with meat quality characteristics. Breeds with greater myofiber number have less intramuscular fat, lighter muscles and smaller water holding capacity, but it was not observed correlation among myofiber number and glicolitic fiber percentage.

O objetivo desse trabalho foi analisar as características miofibrilares de suínos de quatro linhagens distintas e correlacioná-las com a qualidade de carne. Foram utilizados 48 animais (24 machos castrados e 24 fêmeas) provenientes de 4 linhagens, representando os tratamentos experimentais: linhagem melhorada comercialmen-te, selecionada para crescimento e produção de carne magra; linhagem melhorada comercialmen-te, selecionada para fins de prolificidade; animais oriundos do cruzamento Landrace x Large White; e linhagem não melhorada geneticamente. Foram avaliados o comprimento do sarcômero, o tipo de fibra muscular, o número e o diâmetro das células musculares e as características de qualidade da carne (cor, marmoreio e perda de água por gotejamento). O delineamento experimental foi inteiramente casualizado em arranjo fatorial 4 x 2 (4 padrões genéticos e 2 sexos), sendo cada animal uma repetição. Os animais selecionados para deposição de carne, os melhorados para prolificidade e os animais cruzados Landrace x Large White apresentaram maior número de células musculares (p<0,05) que os animais sem seleção. Os animais Landrace x Large White apresentaram o maior diâmetro celular (p<0,05); os animais sem seleção e os selecionados para prolificidade apresentaram as menores médias. Não houve diferença entre as linhagens para o comprimento de sarcômero. Os animais sele-cionados para prolificidade tiveram menor porcentagem de fibras glicolíticas (p<0,05) e maior porcentagem de fibras intermediárias que as demais linhagens (p<0,05). Os animais sele-cionados para deposição de carne e os animais selecionados para prolificidade apresentaram os maiores (p<0,05) e os menores (p<0,05) valores para a perda de água por gotejamento, respectivamente. Os animais sem seleção apresentaram a maior taxa de marmoreio (p<0,05) e carne mais escura (p<0,05), enquanto que os animais selecionados para deposição de carne apresen-taram a menor taxa de marmoreio (p<0,05). Os machos castrados apresentaram carne mais clara que as fêmeas (p<0,05). A análise da correlação indicou que o número de células musculares está associado positivamente com a perda de água por gotejamento e a luminosidade da carne. O número e o tipo de fibras do músculo estão relacionados com as características de qualidade da carne. Genéticas com mais fibras musculares têm menor taxa de gordura intramuscular e apresentam carne mais clara e com menor capacidade de retenção de água, mas não foi observado correlação entre número de fibras musculares e freqüência de fibras glicolíticas.

The effects of vitamin E supplementation (300 mg/kg diet) in the diet of broiler chickens for different periods during rearing on the performance and qualitative traits of breast and leg muscles were evaluated. Seven hundred and twenty day-old chicks were distributed into six treatments: basal diet (25 mg vitamin E/kg diet), and diet supplemented with vitamin E from 1 to 15, 1 to 30, 1 to 45, 14 to 45 and 30 to 45 days of age. Vitamin E content, lipid percentage, TBARS (0 and 3 days of storage), color (*L, *a, *b), and pH were evaluated. There were no differences (p>0.05) among treatments in performance, carcass yield, and cut yields. Qualitative parameters (pH and color) presented no differences, although vitamin E positively affected TBARS values at 3 days of storage, mainly in leg muscles. Vitamin E levels in both muscles were higher in the birds supplemented throughout the experiment.

This study evaluated the use of different probiotics, prebiotics and symbiotics on the quality of carcasses and meat of broiler chickens. One hundred and eight day-old Cobb male broilers were used (n=108) in a completely randomized design according to a 3x3 factorial, with 3 probiotics in the diet (no probiotics, probiotics 1, probiotics 2) and 3 prebiotics in the diet (no prebiotics, prebiotics 1, prebiotics 2). There were nine treatments with 4 replicates and 3 birds per replicate. The results showed that the carcass and cut yields, color (L* - lightness, a* - redness, and b* - yellowness), pH, cooking losses, shearing force and sensory analysis were not affected by the use of different growth promoters at 42 days of age. It was concluded that growth promoters supplemented to the diet did not affect the studied quantitative and qualitative parameters of the carcass and breast meat of broiler chickens.

The present study evaluated the effect of different deboning times on the quality of broiler breast meat. Seventy-two broiler breasts were evaluated. They were distributed in a completely randomized experimental design, with six treatments, six repetitions and two birds per parcel. The treatments were denominated as follows: A - deboning immediately after chilling, B - deboning 1 h after chilling, C - deboning 2 h after chilling, D - deboning 3 h after chilling, E - deboning 4 h after chilling, and F - deboning 24 hours after chilling. Lowest pH values (p<0.05) were seen when deboning was performed 24 h after carcass chilling (pH=6.00) in comparison to deboning at 0 h (6.69) and 1 h (6.42) after chilling. R values were inversely proportional to pH values, i.e., R values were lower (p<0.05) in treatments A (1.05) and B (1.07) when compared to treatment F (1.44). No differences were seen in cooking loss during thermal treatment (broiling) of the muscle P. major. Higher shear forces (p<0.05) were seen in broiled muscles from carcasses with shorter storage times (A - 11.78 kgf and B - 10.75 kgf) before deboning, when compared to treatments E (6.11 kgf) and F (5.64 kgf). Higher L* values were observed in the treatment in which carcass deboning was performed 24 hours after chilling (49.26) in comparison to deboning immediately after chilling (44.68). Therefore, it was concluded that an interval of at least 4 hours is needed between chilling and deboning to obtain broiled breast fillets with tender texture. Furthermore, paler meat color (L* value) was produced with longer carcass storage before deboning.

The present study evaluated the effect of different probiotics on the performance of broiler chickens. A thousand and fifty one-day-old male Cobb chicks were distributed in a completely randomized design in a 3 x 2 + 1 factorial arrangement (3 probiotics sources in the diet, 2 probiotics concentrations in drinking water and 1 control group), with 5 repetitions of 30 birds per parcel. The results showed better feed conversion (p<0.01) (1-21, 22-35 and 1-45 days) and weight gain (p<0.05) (22-35 and 1-45 days) in the control group in relation to the groups receiving probiotics. The use of Bacillus subtilis in the diet improved (p<0.05) feed conversion during the growing phase, but this was not seen in the following period. Thus, it was concluded that probiotics supplementation had no beneficial effects on the performance.

The present work evaluated the effect of different probiotics on carcass and meat quality of broilers. One thousand and fifty male Cobb chicks were distributed at one day of age in a randomized design with 3 x 2 + 1 factorial arrangement (3 probiotics, 2 levels of probiotics in drinking water and 1 negative control group), using 5 replications with 30 birds. Carcass yield was higher (p<0.05) in control birds. Nevertheless, the groups fed with probiotics showed higher (p<0.01) leg yield at 45 days of age. There was a significant decrease in color (lightness) and increase in pH of breast muscle 5 hours after slaughter in the probiotics treated birds. In the sensory analysis, meat flavor and general aspect 72 hours after slaughter were better when probiotics were added in both water and diet. There were no differences in water holding capacity, cooking loss and shearing force among different probiotics or between them and the control. Thus, meat quality was better when probiotics were fed in the water and diet instead of only in the diet. Nevertheless, carcass and meat quality showed no alteration when the control group was compared to birds fed with probiotics, except for leg yield improvement in the latter.