Ana Paula Del Vesco

Effects of Methionine Supplementation on the Expression of Protein Deposition-Related Genes in Acute Heat Stress-Exposed Broilers

The objective of this study was to evaluate the effect of heat stress and methionine supplementation on the gene expression of insulin-like growth factor I (IGF-I), growth hormone receptor (GHR), phosphatidylinositol 3-kinase, and regulatory 1 (PI3KR1) in the liver, as well as the expression of the atrogin 1 and cathepsin L2 (CTSL2) genes in the breast muscle of broilers. Broilers from 1–21 and 22–42 days of age were divided into three treatments related to methionine supplementation as follows: without methionine supplementation (MD), recommended level of methionine (DL1), and excess supplementation of methionine (DL2). The animals were either maintained at a thermal comfort temperature or exposed to heat stress (HS) (38°C for 24 hours, starting on day 20 or day 41 for experiments 1 and 2, respectively). The heat stress increased the body temperature at both ages. Starter period: The HS animals presented increased plasma creatinine content (P<0.0001) and the highest CTSL2 gene expression (P<0.0001). The methionine supplementation increased the IGF-I (P = 0.0144) and GHR (P = 0.0011) gene expression and decreased the CTSL2 (P = 0.0004) and atrogin 1 (P = 0.0012) gene expression. Grower period: Significant effects for the interaction between supplementation and environment were observed for GHR (P = 0.0252) and CTSL2 (P = 0.0011) gene expression. The highest GHR expression was observed in animals that remained in thermal comfort on the DL2 diet, and the lowest expression occurred in the HS animals fed the MD diet. For CTSL2, the HS animals fed the MD diet presented the highest CTSL2 gene expression, and the lowest expression was observed in the animals maintained at thermal comfort on DL1 and DL2 diets. Only methionine supplementation had effect on atrogin-1 gene expression (P<0.0001), with higher methionine content in the diet lower atrogin-1 gene expression was observed. Our results suggest that heat stress induces greater protein degradation and that methionine supplementation could induce protein deposition because methionine increased the expression of genes related to protein synthesis and decreased the expression of genes related to protein breakdown.

Yacare caiman (Caiman yacare) trim hamburger and sausage subjected to different smoking techniques

BACKGROUND Caiman, as well as having skin that, after tanning, produces leather of high added value, exceptional quality and good market value, also possesses a meat with a remarkably smooth taste and appearance. This study aimed to characterize hamburger and sausages made from Yacare caiman (Caiman yacare) meat trim. RESULTS Hot smoked products contained less moisture than the unsmoked products. Protein and ash were higher, respectively, for hot smoked hamburger and sausage. Lipids had greater presence in hot smoked sausage (9.72%), whereas in the burgers they were higher in the liquid smoked burgers (6.71%). The hot smoked products had lower water activity. Hot smoked products displayed less luminance, but the a* and b* chroma were higher in smoked hamburgers. Taste, texture and general acceptability were significant for the hamburger, whereas for the sausage there was a significant effect for texture, salt and purchase intent. CONCLUSION For all the products, the hot smoking resulted in the lowest acceptability.

Comparação das peles de tilápia do Nilo, pacu e tambaqui: Histologia, composição e resistência

The aim of this work was to compare the tilapia (Oreochromis niloticus), pacu (Piaractus mesopotamicus) and tambaqui (Colossoma macroporum) skins on the histology, composition, physico-chemical and physico-mechanical features. Therefore, 10 kg of skins of each species were used. All skins have followed the same methodology for tanning, all processed in tannery machine. Histological and composition analysis were conducted in fresh skin, and 20 leather of each species were used after tanning for physical-chemical and physico-mechanical analysis. The skin of Nile tilapia showed lamellulae larger than the other species examined, however, the deeper layer of the dermis of this species shows collagen fibers thinner in the transverse direction to the skin surface. The Nile tilapia skin had a higher humidity (67.14 %), lipid (1.96 %) and ash contents (1.82 %), though the skin of this species showed the lowest level of crude protein (29.08 %). A higher content of crude protein was found in tambaqui skins (35.70 %). The Nile tilapia leather showed lower thickness (0.68 mm), tensile strength (11.86 N/mm2), progressive tearing (40.18 N/mm), elasticity (52.63 %) and lower maximum strength (81.06 %) compared to pacu and tambaqui leathers. It was observed that the tambaqui leather was the thickest (0.89 mm) and most resistante for the measured variables (tensile strength= 29.49 N/mm2, progressive tearing= 80.01 N/mm and maximum strength= 224.25). Tilapia leathers are less resistant than tambaqui and pacu leathers and the tambaqui leather could be destined for the manufacture of clothing, and the leathers of the three species have thickness within recommended for gloves and clothing manufacture.

Aproveitamento de peles de tilápia-do-nilo congeladas e salgadas para extração de gelatina em processo batelada

The objective was to characterize Nile tilapia skins, freeze- and dry salt dry-preserved to extract gelatins by batch processing. After filleting, the skins were separated from the meat and distributed into two lots: In one, skins were frozen for 7 days (-18 oC); and in the other, skins were salted for seven days (25 oC). The skins were rinsed, weighed and pretreated in H2SO4 a10N solution (pH 3.0), at a 1:6 (skin/water) ratio for 1 h at 24 oC. Gelatin was extracted in water bath at 50 oC for 1 h, and a sample was removed for molecular profiling; the rest was frozen at -18 oC. Physical-chemical analyses were carried out on the skins and liquid gelatins, the molecular profile was obtained from the gelatins, and the skins underwent microbiological analyses. Frozen and salted skins showed, respectively: 78.13% and 76.46% moisture, 18.16% and 19.59% crude protein, 2.26% and 1.90% ether extract, and 1.44% and 2.06% ash, respectively. For the liquid gelatins extracted from frozen and salted skins, moisture was 97.68% and 96.08%, crude protein was 3.18% and 4.12%, ether extract was 0.29% and 0.18%, and ash was 2.31% and 3.03%, respectively. Gel strength and viscosity values were higher for salted skins gelatin (200 g and 19.02 mPas) compared with freeze-preserved skins gelatin (12.7 g and 9.16 mPas). The molecular profile was lower in gelatin extracted from frozen skins, which indicates loss of β and γ-components, which indicates considerable collagen decay from that preservation method.Objetivou-se caracterizar peles de tilapia-do-nilo, conservadas por congelamento e salga a seco, visando a extracao de gelatina em processo batelada. Apos a filetagem, as peles foram descarnadas e distribuidas em dois lotes. Um dos lotes foi congelado a -18 oC por sete dias e o outro foi salgado e mantido a 25 oC por sete dias. As peles foram lavadas, pesadas e pre-tratadas em solucao de H2SO4 a10N (pH 3,0), na proporcao de 1:6 (pele:agua) por uma hora a 24 oC. Extraiu-se a gelatina em banho-maria a 50 oC por uma hora e retirou-se uma amostra para analise do perfil molecular. O restante foi congelado a -18 oC. Foram realizadas analises fisico-quimicas das peles e das gelatinas liquidas, do perfil molecular com as gelatinas e analises microbiologicas das peles. As peles congeladas e salgadas apresentaram, respectivamente, 78,13 e 76,46% de umidade; 18,16 e 19,59% de proteina bruta; 2,26 e 1,90% de extrato etereo e 1,44 e 2,06% de cinzas. Nas gelatinas liquidas extraidas das peles congeladas e salgadas, a umidade foi de 97,68 e 96,08%, o conteudo de proteina bruta de 3,18 e 4,12%, de extrato etereo 0,29 e 0,18% e de cinzas de 2,31 e 3,03%, respectivamente. Os valores da forca de gel e viscosidade foram maiores para a gelatina de peles salgadas (200 g e 19,02mPas) em comparacao a gelatina de peles conservadas pelo congelamento (12,7 g e 9,16mPas). O perfil molecular foi menor na gelatina extraida a partir de peles congeladas, portanto houve perda de β e γ-componentes, que indica grande degradacao do colageno decorrente do metodo de conservacao.

Pre-Slaughter Stress Affects Ryanodine Receptor Protein Gene Expression and the Water-Holding Capacity in Fillets of the Nile Tilapia.

Current study evaluated the effect of pre-slaughter stress on serum cortisol levels, pH, colorimetry, water-holding capacity (WHC) and gene expression of ryanodine receptors (RyR1 and RyR3) in the Nile tilapia. A 3x4 factorial scheme experiment was conducted comprising three densities (100, 200, 400 kg/m³) with four transportation times (60, 120, 180, and 240 minutes).Transportation times alone reduced cortisol levels up to 180 minutes, followed by increased WHC and mRNA expression, RyR1 and RyR3 (200 kg/m³ density). No effect of density x transportation time interacted on the evaluated parameters. Results provided the first evidence that pre-slaughter stress affected ryanodine gene expression receptors and, consequently, the water-holding capacity in tilapia fillets.

Qualidade microbiológica e vida útil de filés defumados de tilápia-do-nilo sob refrigeração ou congelamento

The objective of this work was to evaluate the microbiological quality and shelf life of Nile tilapia fillets subjected to different smoking methods and storing conditions. Two smoking processes (cold or hot) were used in fillets with or without pigmentation. Products were stored under refrigeration or freezing, and monitored continually for 28 days for evaluation of their shelf life. Frozen fillets were monitored for 146 days for analysis of thiobarbituric acid (TBA) only. Hot- and cold-smoking reduced the coliform quantity, respectively, by 99.78% and 97.80%. Product storage under refrigeration allowed a 99.73% coliform reduction, and storage under freezing reduced them by 99.83%. Fecal coliform values were within the allowed limits. TBA values in fillets reached their maximum on the 14th storage day. TBA values were higher in treatments under refrigeration storage than in those under freezing, as well as in cold-smoked fillets in comparison to the hot-smoked ones. Hot-smoked process, followed by refrigeration storage, is the most adequate technique to ensure quality and a larger shelf life for Nile tilapia fillets, regardless of pigmentation process.

The role of cinnamon as a modulator of the expression of genes related to antioxidant activity and lipid metabolism of laying quails

Since cinnamon has vitamins and minerals in addition to antioxidants compounds in its chemical composition studies have shown the potential of cinnamon supplementation on some important characteristics in the performance of birds. Thus, this study was conducted under the hypothesis that the inclusion of cinnamon in the laying quail diet could influence the performance of the birds through the expression of genes related to antioxidant activity and lipid metabolism. To test this hypothesis, 144 Japanese quail (Coturnix japonica) with an initial age of 18 weeks and average weight of 133g were distributed in a completely randomized design with two treatments: no cinnamon supplementation (NCS—control group) and with supplementation of 9g/kg of cinnamon powder (CPS). The experiment lasted for 84 days. At the end of the experimental period, six animals from each treatment were euthanized by cervical dislocation, blood was collected and organs weighed. Liver tissue was collected for gene expression and biochemical analyses. We observed a significant effect of cinnamon inclusion on the weight of the pancreas (P = 0.0418), intestine (P = 0.0209) and ovary (P = 0.0389). Lower weights of the pancreas and intestine, and a higher ovary weight was observed in birds receiving the CPS diet. Quails fed with cinnamon supplementation also had better feed conversion per egg mass (2.426 g /g, P = 0.0126), and higher triglyceride (1516.60 mg/dL, P = 0.0207), uric acid (7.40 mg/dL, P = 0.0003) and VLDL (300.40 mg/dL, P = 0.0252) contents. A decreased content of thiobarbituric acid reactive substances (TBARS) and lower catalase activity was observed in the liver of quails from the CPS diet (0.086 nmoles/mg PTN, and 2.304 H2O2/min/mg PTN, respectively). Quails from the CPS group presented significantly greater expression of FAS (fatty acid synthase, 36,03 AU), ACC (Acetyl-CoA Carboxylase, 31.33 AU), APOAI (apolipoprotein A-I, 803,9 AU), ESR2 (estrogen receptor 2, 0.73 AU) SOD (superoxide dismutase, 4,933.9 AU) and GPx7 (glutathione peroxidase 7, 9.756 AU) than quails from the control group. These results allow us to suggest that cinnamon powder supplementation in the diet of laying quails can promote balance in the metabolism and better performance through the modulation of antioxidant activity and the expression of genes related to lipid metabolism.

Características de resistência dos couros de Pseudoplatystoma sp submetidos a alterações nas etapas do processo de curtimento

O objetivo do experimento foi avaliar a resistencia dos couros de surubim ( Pseudoplatystoma sp ), submetidos a alteracoes nas etapas de curtimento, em funcao dos diferentes tempos de acao do caleiro, niveis de enzimas utilizadas na etapa de purga, curtimento com e sem sais de cromo, niveis de oleos utilizados na etapa de engraxe e diferentes tecnicas de processamento. Foram realizados cinco ensaios. No ensaio I, os couros submetidos ao caleiro por 1 hora apresentaram maior (78,89 N/mm) resistencia ao rasgamento progressivo e forca maxima (73,50N) e nao houve diferenca significativa para tracao, alongamento e forca maxima para estes testes. No ensaio II, os couros que receberam 0,7% de enzima proteolitica por 40 minutos apresentaram maior resistencia a tracao (43,80 N/mm 2 ) e elasticidade (78,06%), apesar de nao diferir do tratamento com adicao do mesmo percentual de enzima, de forma parcelada (39,92 N/mm 2 e 71,07%). Nao houve diferenca para rasgamento progressivo (84,17 N a 96,86 N). No ensaio III e IV, os couros nao apresentaram diferencas significativas para os testes de resistencia. No ensaio V, os couros do tratamento tres (curtimento mais comum) utilizaram maior forca no teste (225,81 N) e apresentaram maior elasticidade (71,81%). Nao houve diferenca significativa para tracao. Os couros do tratamento um, apresentaram maior (118,59 N/mm) resistencia ao rasgamento progressivo. Com os resultados obtidos desse couro, pode ser observada a elevada resistencia a tracao, alongamento e rasgamento progressivo, podendo ser utilizado em vestuario, sapatos e artefatos em geral pela sua beleza e resistencia, valorizando o produto em que for aplicado o couro, alem de reduzir o possivel impacto ambiental em funcao do descarte dessa materia-prima.