Características produtivas, carcaça, cortes e resposta imune humoral de frangos de corte alimentados com diferentes fontes de óleo e vitamina E / Productive and humoral immune response of broilers fed with different sources of oil and vitamin E

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.(AU)

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.(AU)

Detection of Salmonella spp, Salmonella Enteritidis and Typhimurium in naturally infected broiler chickens by a multiplex PCR-based assay.

The presence of Salmonella in the intestinal tract, on the chickens skin and among their feathers, may cause carcasses contamination during slaughtering and processing and possibly it is responsible by the introduction of this microorganism in the slaughterhouses. A rapid method to identify and monitor Salmonella and their sorovars in farm is becoming necessary. A pre-enriched multiplex polymerase chain reaction (m-PCR) assay employing specific primers was developed and used to detect Salmonella at the genus level and to identify the Salmonella enterica serovar Enteritidis (S. Enteritidis) and Salmonella enterica serovar Typhimurium (S. Typhimurium) in broiler chicken swab samples. The method was validated by testing DNA extract from 90 fresh culture cloacal swab samples from poultry chicken cultured in phosphate buffer peptone water at 37 °C for 18 h. The final results showed the presence of Salmonella spp. in 25% of samples, S. Enteritidis was present in 12% of the Salmonella-positive samples and S. Typhimurium in 3% of the samples. The m-PCR assay developed in this study is a specific and rapid alternative method for the identification of Salmonella spp. and allowed the observation of specific serovar contamination in the field conditions within the locations where these chickens are typically raised.

Skeletal muscle calcium channel ryanodine and the development of pale, soft, and exudative meat in poultry.

The development of pale, soft, and exudative (PSE) breast fillet meat has become an economic burden for the poultry industry worldwide. PSE meat results in 1.0-1.5% loss in moisture and carcass weight, and a 2010 estimate of the Brazilian annual production put the economic loss due to PSE at over US$30 million. In the USA, PSE has caused an annual loss of up to US$200 million to the poultry industries. The underlying causes of the color abnormality in PSE meat are not fully understood. However, the likely physiological origin of PSE broiler meat is an excessive release of Ca(2+) promoted by a genetic mutation of the ryanodine receptor (RYR), a Ca(2+)-channel protein in the skeletal muscle sarcoplasmic reticulum. In pigs, the genetic cause of PSE meat has been identified as a point mutation in the RYR1 gene at nucleotide 1843, which causes an amino acid substitution (Arg615 to Cys615) in the RYR. This mutation leads to an alteration in Ca(2+) homeostasis, hypermetabolism, intense muscle contraction, and malignant hyperthermia in pigs susceptible to porcine stress syndrome. An understanding of this process represents the basis for breeding strategies aimed at eliminating the RYR1 mutation from global pig populations, a strategy that the poultry industry intends to emulate. The aim of this study was to review the subject, with an emphasis on the most recent developments in the field.

Detection of Salmonella spp, Salmonella Enteritidis and Typhimurium in naturally infected broiler chickens by a multiplex PCR-based assay

The presence of Salmonella in the intestinal tract, on the chickens skin and among their feathers, may cause carcasses contamination during slaughtering and processing and possibly it is responsible by the introduction of this microorganism in the slaughterhouses. A rapid method to identify and monitor Salmonella and their sorovars in farm is becoming necessary. A pre-enriched multiplex polymerase chain reaction (m-PCR) assay employing specific primers was developed and used to detect Salmonella at the genus level and to identify the Salmonella enterica serovar Enteritidis (S. Enteritidis) and Salmonella enterica serovar Typhimurium (S. Typhimurium) in broiler chicken swab samples. The method was validated by testing DNA extract from 90 fresh culture cloacal swab samples from poultry chicken cultured in phosphate buffer peptone water at 37 ºC for 18 h. The final results showed the presence of Salmonella spp. in 25% of samples, S. Enteritidis was present in 12% of the Salmonella-positive samples and S. Typhimurium in 3% of the samples. The m-PCR assay developed in this study is a specific and rapid alternative method for the identification of Salmonella spp. and allowed the observation of specific serovar contamination in the field conditions within the locations where these chickens are typically raised.

A new single nucleotide polymorphism in the ryanodine gene of chicken skeletal muscle.

Some genes affect meat quality in chickens. We looked for polymorphisms in the Gallus gallus α-RyR gene (homologous to RyR 1) that could be associated with PSE (pale, soft and exudative) meat. Because RyR genes are over 100,000 bp long and code for proteins with about 5000 amino acids, primers were designed to amplify a fragment of hotspot region 2, a region with a high density of mutations in other species. Total blood DNA was extracted from 50 birds, 25 that had PSE meat and 25 normal chickens. The DNA samples were amplified by PCR, cloned, sequenced, and used to identify single nucleotide polymorphisms (SNPs). The amplified fragment of α-RyR was 604 nucleotides in length; 181 nucleotides were similar to two exons from a hypothetical turkey cDNA sequence for α-RyR. A non-synonymous nucleotide substitution (G/A) was identified in at least one of the three sequenced clones obtained from nine animals, six PSE (HAL+) birds and three normal (HAL-) birds; they were heterozygous for this mutation. This SNP causes a change from Val to Met in the α-RYR protein. Since the frequencies of this SNP were not significantly different in the PSE versus normal chickens, it appears that this mutation (in heterozygosity) does not alter the structure or function of the muscle protein, making it an inappropriate candidate as a genetic marker for PSE meat.

Heat and chemical stress modulate the expression of the alpha-RYR gene in broiler chickens.

The biological cause of Pork Stress syndrome, which leads to PSE (pale, soft, exudative) meat, is excessive release of Ca(2+) ions, which is promoted by a genetic mutation in the ryanodine receptors (RyR) located in the sarcoplasmic reticulum of the skeletal muscle cells. We examined the relationship between the formation of PSE meat under halothane treatment and heat stress exposure in chicken alphaRYR hot spot fragments. Four test groups were compared: 1) birds slaughtered without any treatment, i.e., the control group (C); 2) birds slaughtered immediately after halothane treatment (H); 3) birds slaughtered immediately after heat stress treatment (HS), and 4) birds exposed to halothane and to heat stress (H+HS), before slaughtering. Breast muscle mRNA was extracted, amplified by RT-PCR, and sequenced. PSE meat was evaluated using color determination (L* value). The most common alteration was deletion of a single nucleotide, which generated a premature stop codon, resulting in the production of truncated proteins. The highest incidence of nonsense transcripts came with exposure to halothane; 80% of these abnormal transcripts were detected in H and H+HS groups. As a consequence, the incidence of abnormal meat was highest in the H+HS group (66%). In HS, H, and C groups, PSE meat developed in 60, 50, and 33% of the samples, respectively. Thus, halothane apparently modulates alphaRYR gene expression in this region, and synergically with exposure to heat stress, causes Avian Stress syndrome, resulting in PSE meat in broiler chickens.

Growth and carcass characteristics of pasture fed LHRH immunocastrated, castrated and intact Bos indicus bulls.

The effectiveness of a luteinizing hormone-releasing hormone (LHRH) fusion protein vaccine or surgical castration, at two years of age, on growth and carcass characteristics of Bos indicus bulls was evaluated. Seventy Nelore-cross bulls were divided into three groups: (1) immunized, (2) castrated and (3) intact control. At slaughter (three years of age), intact bulls had higher body weights, ADG, carcass weights, and muscle percentage compared to immunized and surgically castrated animals. Both castrated and immunized animals had greater marbling and percent carcass fat than the intact bulls. Average tenderness scores were inferior for intact bulls compared to immunized and castrated animals, but these differences were not significant (P>0.05). Juiciness, flavor, thawing, nor cooking losses differed significantly among the three groups. Immunocastration was effective in producing carcass traits similar to that of surgical castration. Therefore, immunization with LHRH fusion proteins appears to have practical utility in the management and castration of grazing bulls.

Increase of interstitial collagen in the mouse endometrium during decidualization.

Decidualization in the mouse consists of an extensive remodeling of the endometrial extracellular matrix, resulting in a reduction of the extracellular spaces, an increase in the diameter of collagen fibrils, and changes in the relative ratio of different types of glycosaminoglycans. To assess the dynamic changes of the endometrial extracellular matrix during decidualization, collagen was analyzed biochemically and immunochemically in the endometrium of nulliparous and day 5 to day 8 pregnant mice. The amount of collagen per gram dry weight was higher in the endometrium of implantation sites than in interimplantation sites. Collagen types I, III, and V were the main components of the endometrium of nulliparous and pregnant animals. The amount of collagen type V was higher in the endometrium of pregnant animals than in nulliparous ones. A relative unusual homotrimeric form of collagen type V, probably formed by [alpha1(V)](3), was detected in pregnant endometrium by gel eletrophoresis and immunoblotting.

Evaluation of survival of Staphylococcus aureus and Clostridium botulinum in charqui meats.

Charqui meats were prepared in laboratory conditions in order to carry out experiments to observe the possibility of development of enterotoxigenic Staphylococcus aureus and Clostridium botulinum proteolytic type B spores and their toxins. Results demonstrated that the harsh processing conditions, high salt concentration, relative high temperature, a(w) values, inhibited the growth of both bacteria. Under our experimental conditions, S. aureus would survive throughout the sequence of salting steps i.e. brine followed by rock salting and the sunshine drying step. However, at final a(w) value of 0.70-0.75 would create conditions to inhibit its development. The other experiment revealed that C. botulinum spores germination also was impaired because of these low a(w) values. Under these conditions, charqui meats revealed to be safe products in relation to toxins from both enterotoxigenic S. aureus and C. botulinum.

Charqui meats as fermented meat products: role of bacteria for some sensorial properties development.

Jerked beef, a derivative of charqui meat, is a cured, salted and dried meat product. The presence of halotolerant bacteria, where Staphylococcus spp. (84.2%) were the predominant species, would act eventually as starter cultures and was followed throughout processing. Jerked beef prepared separately with exogenous S. carnosus and S. xylosus as starter cultures resulted in high proteolysis. Samples prepared with S. xylosus had the highest proteolysis and were preferred by the sensory panel. This research has suggested that jerked beef (and thus charqui meat) prepared under these conditions is a fermented meat product.

Hamburger meat identification by dot-ELISA.

The use of low cost meats to adulterate meats and meat products has been reported. Appropriate methods of analysis then are needed in order to detect this practice. The dot-ELISA method was used to identify the meat of different animal species and to detect adulteration of hamburgers. Antisera to bovine, chicken, swine and horse albumin were produced and they could detect the meat extract of the homologous species at concentrations as low as 0.6%. Thus, the anti-albumin antisera could identify bovine, chicken, swine and horse meat with adequate specificity and sensitivity both in isolation and when added to hamburger. Commercial samples of bovine, chicken and swine hamburgers showed no adulteration with bovine, chicken, swine or horse meats. Our expectation of hamburger adulteration was not confirmed.

An ultrastructural observation on charquis, salted and intermediate moisture meat products.

Charqui meats are tropical intermediate moisture meat products containing 45% moisture and 15% salt with an A(w) of 0.70-0.75. Light microscopic studies of a charqui derivative popularly known as Jerked beef (JB) demonstrated considerable shrinking of muscle cells and the formation of fluid channels. The area occupied by muscle cells in JB was diminished by 30-40% in comparison with control samples. At the ultrastructural level, A-bands including the M-line disappeared indicating proteins were lost during processing. Z-lines appeared to be fragmented. In the enlarged extracellular spaces, collagen fibers retained their banding patterns although an empty space was observed surrounding these fibers. The denaturation of myofibrillar proteins during processing and the osmotic pressure caused by salting create conditions for water movement from the myofibrillar compartments to the intermyofibrillar space, then to the extracellular matrix and ultimately to the meat surface.

Parameters determining the quality of charqui, an intermediate moisture meat product.

Charqui is a typical Brazilian meat product obtained by salting and sun-drying beef samples. The chemical, physical and microbiological characteristics of the charqui were evaluated throughout processing and storage. The results confirm charqui is an intermediate moisture meat product (A(w) = 0·70-0·75). A close relationship between moisture, pretein and ash vaiues was found, suggesting the possibility of using the resulting charqui A(w) value as a parameter to define the product instead of the official moisture and mineral residue contents. The TBA determination, which expresses the state of lipid oxidation, rapidly reached the maximum value, corroborating the previous observations on the salt pro-oxidant role, and then decreased gradually. A gradual decrease in microorganism count during processing and storage of charqui was also observed. These results indicate the feasibility of obtaining a final product with a low level of microbial count when raw materials of good quality, and adequate handling conditions, are used for charqui production.

Effect of salt on oxidative changes in pre- and post-rigor ground beef.

Pre- and post-rigor beef was ground and salt was added to give 0·0, 0·5, 2·0 and 4·0% NaCl (w/w). Samples were removed after 0, 24, 48, 72 and 96 h at 4°C and analyzed for pH, TBA numbers and percentages of reduced myoglobin (Mb), metmyoglobin (MMb) and oxymyoglobin (MbO(2)). After holding for 96 h the samples were cooked in a boiling water bath to an internal temperature of 80°C and held at 4°C for 48 h before TBA analysis. Pre-rigor grinding and salting reduced the post-mortem pH decline and the extent of meat discoloration as shown by the differences in the amount of MMb. The extent of lipid oxidation as measured by TBA numbers was not significantly different for the pre- and post-rigor ground salted meat samples, although salt accelerated oxidation during storage. Results demonstrated that pre-rigor grinding and salting of beef produces a more stable bright red color, which appears to be associated with a lower percentage of MMb and a higher ultimate pH in the pre-rigor salted meat.

Immunofluorescence localization of type-M collagen in articular cartilage.

Normal mammalian articular cartilage has been found to contain several collagenous peptide chains in addition to type-II collagen. We now report the distribution in adult pig cartilage of one of these new peptides, type-M collagen, using type-specific antibodies. Type M is primarily located in the pericellular environment of the cells in the deeper zones of the articular cartilage. The distribution is shown to be distinct from that of type-II collagen. This finding suggests that type-M collagen may play an important role in the metabolism of articular cartilage.

Identification of two further collagenous fractions from articular cartilage.

Salt fractionation of pepsin-solubilized human and porcine articular cartilage has revealed the presence of two further collagenous fractions, CF1 and CF2, at high salt concentration following the precipitation of Type-II, 1 alpha, 2 alpha, 3 alpha, and Type-M collagens. Both fractions precipitate at 2.0 M NaCl, but higher yields of CF1 are obtained at 3.0 M NaCl. CF1 and CF2 can be separated in the native form using carboxymethyl-cellulose chromatography. Under denaturing conditions, CF1 has an apparent molecular weight of 25 000 and is unaffected by mercaptoethanol, whereas CF2 has a molecular weight of 35 000 before and 12 000 after reduction by mercaptoethanol. These fractions are probably fragments derived from larger collagen molecules, although the cyanogen bromide digest studies suggest that they are derived from a collagenous type other than one of those previously identified in cartilage.

The chemistry of the collagen cross-links. Age-related changes in the reducible components of intact bovine collagen fibres.

The change in the amounts of the three major reducible cross-links was followed throughout the bovine-life span. The major reducible cross-link in embryonic skin is 6,7-dehydro-N(epsilon) -(2-hydroxy-5-amino-5-carboxypentyl)hydroxylysine, but this is gradually replaced in the latter stages of gestation or early postnatal growth period by two other Schiff bases, 6,7-dehydro-N(epsilon)-(5-amino-5-carboxypentyl)hydroxylysine and a component not yet identified, designated Fraction C. These latter two Schiff bases increase in amount during the rapid growth period to a maximum, after which they then slowly decrease until at maturity they are virtually absent. The proportion of these Schiff bases closely reflects the rate of growth, i.e. the amount of newly synthesized collagen present at any one time. Similarly, the three Schiff bases present in tendon and the one in cartilage slowly decrease during maturation. No evidence for the possible stabilization of these aldimine bonds during maturation by reduction in vivo was found by three different analytical techniques. Concurrently with the decrease in the proportion of the Schiff bases some new reducible components increased during maturation, but their characterization as N(epsilon)-glycosylamines demonstrated that they were not related to the lysine-derived aldehyde components. The significance of these components in the aging process cannot at present be assessed. As no evidence was obtained for any new reducible cross-links replacing the Schiff bases, it is probable that the latter are intermediate cross-links and that during maturation they are stabilized to some as yet unknown non-reducible cross-link as previously proposed (Bailey, 1968).