Is beef quality affected by the inclusion of distiller grains in cattle diets?

This study aimed to analyze the effect of including increasing levels of distiller grains (DG) in beef cattle feeding diets on meat quality from an integral approach. To this end, we analyzed the meat from 36 yearling steers fed with four dietary treatments: 0DG (control corn-based diet), 15DG, 30DG, and 45DG (containing 15%, 30%, or 45% of DG on DM basis). Crude protein, ash, and fat contents of diets increased with DG level. The fatty acid profile of DG diets was reflected in the fatty acid profile of plasma samples. Feeding diets with DG had no effect on the biochemical parameters analyzed in plasma. In addition, it did not influence the water holding capacity, the muscle or fat color at 72 h post mortem or at retail display, or the contents of SFAs, MUFAs, and PUFAs in beef. The DG diets led to lower values of cooking loss. Meat from 15DG and 30DG showed greater percentage of troponin C and fragments of 30 to 27 kDa than meat from 45DG. Also, meat from 30DG showed the lowest values of Warner-Bratzler shear force. Hence, including up to 30% corn DG in beef cattle feeding diets had positive effects on meat quality.

Effect of Aging and Retail Display Conditions on the Color and Oxidant/Antioxidant Status of Beef from Steers Finished with DG-Supplemented Diets.

The aim of this work was to study the effect of finishing diets including distiller grains (DG) on color and oxidative stability of beef after being exposed to aerobic retail display conditions, with or without previous aging. For this purpose, beef samples from animals fed with finishing diets including 0%, 15%, 30%, and 45% DG (on a dry matter basis), which had been exposed to aerobic retail display conditions, with or without previous aging under vacuum packaging, were evaluated. The content of γ-tocopherol, ß-carotene, and lutein in diet samples increased with the level of DG. Beef evaluated at 72 h post-mortem showed greater content of γ-tocopherol and retinol as the DG level increased. Meat color was not affected by DG inclusion, but color parameters decreased with retail conditions. Meat from animals fed with DG showed the lowest values of thiobarbituric acid reactive substances (TBARS), independently of the retail display conditions. However, all samples were below the threshold associated with rancid aromas and above the a* value related to meat color acceptance. Thus, feeding diets including up to 45% of DG improved the antioxidant status of meat, preserving the color, and delaying lipid oxidation in meat samples under the display conditions evaluated.

Dietary inclusion of ruminally protected linseed oil as a means to mitigate heat and slaughter-induced stress in feedlot cattle.

There is evidence of a relationship between increased energy intake and the development of metabolic inflammation and insulin resistance (IR), and between the aforementioned metabolic state and impaired tolerance to heat stress. Based on the anti-inflammatory properties and mitigating effects on IR and stress of n-3 polyunsaturated fatty acids (n-3 PUFA), an experiment was performed to evaluate the effect of n-3 PUFA supplementation to feedlot-finished steers during summer on animal performance, physiological and biochemical variables associated with glucose metabolism, heat and preslaughter-induced stress, and meat quality. A total of 48 Angus steers (388 ± 2 kg) were fed one of three corn-based finishing diets containing (dry matter basis) 0% added oil (CON; negative control), or 1.90% of sunflower oil-calcium salt (SUN; positive control), or 1.92% of linseed oil-calcium salt (LIN). There was a trend (P = 0.08) for greater dry matter intake (DMI) and greater (P = 0.02) average daily gain (ADG) in LIN-fed animals compared with the average between those that received the CON or SUN diets, whereas no differences (P ≥ 0.34) were observed between the latter. No other performance, physiological, or carcass variables were affected (P ≥ 0.12) by treatment. Blood glucose and insulin were similar (P ≥ 0.14), though the homeostatic model assessment (HOMA) which gauges IR tended (P = 0.06) to be reduced for LIN-fed animals compared with the average between those that received the CON or SUN diets. Blood insulin and HOMA increased linearly (P ≤ 0.01) with days on feed. An interaction between the study phase (feeding period or slaughter) and treatment was observed (P ≤ 0.05) for glucose and cortisol. While the magnitude of glucose increase (P < 0.01) from the end of the feeding period to slaughter was greater for CON- and SUN-fed animals compared with LIN-fed ones, cortisol increased (P < 0.05) only in animals that received CON or SUN diets. Meat quality attributes were not affected (P ≥ 0.16) by treatment. The concentration of n-3 PUFA was greater (P < 0.01) and n-6:n-3 ratio was lesser (P < 0.01) in meat from LIN-fed animals compared with that resulting from the average between the animals that received the negative (CON) or positive (SUN) control diets. Results suggest that n-3 PUFA supplementation mitigated metabolic alterations associated with IR and preslaughter-related stress. It may have also improved tolerance to heat, resulting in greater DMI and ADG of steers fed a high-energy diet during summer. Results also indicate that glucose metabolism and heat stress tolerance worsen with time when feeding concentrate-based diets.

Polyunsaturated fatty acids (n-3 PUFA) of diets have anti-inflammatory properties and mitigating effects on insulin resistance (IR) and stress in steers. This study evaluated the effect of n-3 PUFA supplementation to feedlot-finished steers during summer on animal performance, physiological and biochemical response, and meat quality. We found that n-3 PUFA supplementation mitigated metabolic alterations associated with IR and slaughter-related stress. It may have also improved tolerance to heat, resulting in greater dry matter intake, and average daily gain of steers fed a high-energy diet during summer.

Feeding strategies and ageing time alter calpain system proteins activities and meat quality of Braford steers.

OBJECTIVE: The aim of this study was to evaluate the effect of ageing and feeding strategies on the calpain protease system and meat quality traits in Braford steers. METHODS: Thirty Braford steers were employed; 15 animals were supplemented with corn silage during finishing and 15 were kept only on pasture. Meat quality traits and calpain system protein activity were evaluated in longissimus thoracis et lumborum (LTL) steaks aged for 2, 7, 14, and 21 days. RESULTS: Aged meat showed higher pH and calcium content, while Warner Bratzler shear force (WBSF) decreased to day 21. No interaction between ageing and diet was seen for quality traits. Steers finished with corn silage showed higher values of water holding capacity, WBSF and free calcium, and lower values of pH and cooking loss. Calpain and calpastatin activities decreased with ageing. Finishing steers on pasture produced higher values of calpains and lower values of calpastatin activities. The higher values of calpain 1 activity were observed in muscles aged 2 days from pasture finished animals, and the lower activity of the inhibitor in the 21 days aged samples of the same group. CONCLUSION: These results suggest a diet by ageing interaction in calpains and calpastatin and this interaction impact in Warner Bratzler Shear Force in Braford LTL muscle.

Feeding strategies alter gene expression of the calpain system and meat quality in the longissimus muscle of Braford steers.

OBJECTIVE: The aim of the present study was to determine the effect of supplementing pasture-finished steers with corn silage on the expression level of the calpain system proteins and beef tenderization. METHODS: Thirty Braford steers grazing on summer pasture were used for the study. For 120 days fifteen animals were supplemented with corn silage at 1% of body weight per head per day (Suppl) whereas the remaining 15 steers only received pasture (Contr). Carcass and meat traits were evaluated and compared between groups. Gene expression and activities of proteases (calpain 1 and calpain 2) and inhibitor (calpastatin) were measured using real-time polymerase chain reaction and casein zymography. RESULTS: Carcass and meat traits were significantly different between feeding systems. Supplemented steers showed higher hot carcass weight (p<0.01), fat content (p = 0.02), and Warner-Bratzler shear force (p = 0.03). Furthermore, the control group showed higher protease:inhibitor ratios, at mRNA (p = 0.01) and protein levels (p<0.10). Warner-Bratzler shear force and mRNA calpains:calpastatin ratio were associated in both feeding systems (p<0.01). CONCLUSION: Based on the results obtained in the study, beef tenderness differences among finishing strategies could be modulated through differential expression of the calpain system proteins.

Determinación de la composición nutricional de la carne de pollo argentina / Measurement of nutritional composition of Argentinean chicken meat

Introducción: La información sobre carne de pollo disponible en la tabla de composición nutricional local pertenece aproximadamente a la década de 1950, y está limitada a pocos cortes. Es necesario contar con datos actualizados de composición nutricional de pollos en Argentina. Objetivo: Determinar la composición nutricional de pechuga y pata-muslo de pollos de Argentina. Materiales y método: Estudio descriptivo de 27 unidades muestrales provenientes de 10 frigoríficos de Argentina. Se obtuvieron muestras de pata-muslo y pechuga, con y sin piel, para determinar: contenido de agua, proteínas, grasa total, ceniza y energía, y en las muestras sin piel: potasio, sodio, fósforo, hierro y perfil de ácidos grasos. Se aplicaron metodologías AOAC y FSIS SDM2 FSIS MTL-1. Resultados: En pechuga y pata muslo sin piel se obtuvo: 107(DE 4) y 127 (DE 8) kcal; 23,7 (DE 1,0) y 19,9 (DE 1,0) g de proteínas;1,4 (DE 0,3) y 5,3 (DE 0,7) g de grasa: grasas saturadas 375(DE 23,3) y 1367 (DE 71,8) mg, monoinsaturadas 418 (DE 45,9)y 1829 (DE 110,0) mg, poliinsaturadas 432 (DE 35,4) y 1657 (DE151,4) mg, trans 27 (DE 6,1) y 54 (DE 36,3) mg; sodio 47 (DE 4)y 74 (DE 5) mg; potasio 355 (DE 21) y 307 (DE 18) mg; fósforo235 (DE 11) y 195 (DE 10) mg; hierro 0,31 (DE 0,03) y 0.60 (DE0.05) mg respectivamente, cada 100 g de parte comestible. En pechuga y pata muslo con piel se obtuvo: 161 (DE 14) y 200 (DE20) kcal; 20,2 (DE 1,1) y 17,0 (DE 0,8) g de proteínas; 8,9 (DE 1,5)y 14,7 (DE 2,2) g de grasas totales respectivamente, cada 100 g de parte comestible. Conclusión: La carne de pollo argentina es fuente de proteínas, baja en lípidos totales, con predominio de ácidos grasos insaturados. Aporta el 11% de la Ingesta Adecuada de potasio, el 46% de la Recomendación Dietética Admitida de fósforo, el 9 y 4% de la de hierro para el hombre y la mujer, y sólo el 5% de la ingesta diaria máxima de sodio.

Introduction: Nutritional composition data of chicken meatavailable in local charts, dates back to 1950 and is limited to afew cuts. It is essential to have nutritional composition data ofchicken meat in Argentina updated. Objectives: To specify nutritional composition of chickenmeat -breast and leg- in Argentina.Materials and method: A descriptive study of 27 sampleunits coming from 10 cold stores in Argentina. Leg and breastsamples were obtained, with and without skin, to determine:water content, proteins, total fat, ash and energy and in theskinless samples: potassium, sodium, phosphorous, iron andfatty acids profile. AOAC and FSIS SDM2 FSIS MTL-1 methodologieswere used.Results: Results obtained out of breast and leg without skin(every 100 g of edible portion): 107 (SD 4) and 127 (SD 8) kcal,23.7 (SD 1.0) and 19.9 (SD 1.0) g of proteins, 1.4 (SD 0.3) and 5.3(SD 0.7) g of fat, saturated fats 375 (SD 23.3) and 1367 (DS 71.8)mg, monounsaturated 418 (SD 45,9) and 1829 (SD 110,0) mg, polyunsaturated 432 (SD 35.4) and 1657 (SD 151,4) mg, trans27 (SD 6.1) and 54 (SD 36.3) mg, sodium 47 (SD 4) and 74 (SD5) mg, potassium 355 (SD 21) and 307 (SD 18) mg, phosphorous235 (SD 11) and 195 (SD 10) mg, iron 0.31 and 0.60 mg,respectively. Out of breast and leg with skin (every 100 g ofedible portion): 161 (SD 14), and 200 (SD 20) kcal, 20.2 (SD 1.1)and 17.0 (SD 0.8) g of proteins, 8.9 (SD 1.5) and 14.7 (SD 2.2) gof total fats, respectively.Conclusion: Argentinean chicken meat is a source of protein,low in total lipids, with a predominance of unsaturated fattyacids. It provides 11% of the Adequate Intake for potassium, 46% of the Recommended Dietary Allowance (RDA) for phosphorous,9 and 4% of the RDA for iron in men and women, respectivelyand just 5% of the maximum daily intake of sodium.

A Contribution of Beef to Human Health: A Review of the Role of the Animal Production Systems.

Meat and meat products constitute important source of protein, fat, and several functional compounds. Although beef consumption may implicate possible negative impacts on human health, its consumption can also contribute to human health. Quality traits of beef, as well as its nutritional properties, depend on animal genetics, feeding, livestock practices, and post mortem procedures. Available data show that emerging beef production systems are able to improve both, quality and nutritional traits of beef in a sustainable way. In this context, Argentina's actions are aimed at maximising beef beneficial effects and minimising its negative impact on human health, in a way of contributing to global food security.

Storage lipids and proteins of Euterpe edulis seeds.

Comparative studies on fatty acid and protein composition of the endosperm and embryo of palmito (Euterpe edulis Martius) were conducted using gas-liquid chromatography and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. On a dry weight basis, the embryo contained extremely lower amounts of lipids and proteins than did the endosperm, which was associated with the scarce lipid and protein bodies previously reported in axis and cotyledon. The fatty acid composition also exhibited differences between both tissues: (I) the fatty acid diversity was greater in embryo than in endosperm; (II) embryo and endosperm contained predominantly linoleic, palmitic, oleic and stearic acids even though the relative values were different for each tissue. As compared to other palm species, the higher fatty acid unsaturation in Euterpe edulis seed could be involved in the previously reported short longevity and recalcitrant behavior during storage. Proteins of both tissues were heterogeneous in molecular mass. Some proteins were tissue-specific, but other were common, among them a highly glycosylated protein which migrated at about 55 kDa. We hypothesize that the latter, also reported in all previously studied palm species, is one of the proteins characterizing the Arecaceae family.

Storage lipids and proteins of Euterpe edulis seeds

Comparative studies on fatty acid and protein composition of the endosperm and embryo of palmito (Euterpe edulis Martius) were conducted using gas-liquid chromatography and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. On a dry weight basis, the embryo contained extremely lower amounts of lipids and proteins than did the endosperm, which was associated with the scarce lipid and protein bodies previously reported in axis and cotyledon. The fatty acid composition also exhibited differences between both tissues: (I) the fatty acid diversity was greater in embryo than in endosperm; (II) embryo and endosperm contained predominantly linoleic, palmitic, oleic and stearic acids even though the relative values were different for each tissue. As compared to other palm species, the higher fatty acid unsaturation in Euterpe edulis seed could be involved in the previously reported short longevity and recalcitrant behavior during storage. Proteins of both tissues were heterogeneous in molecular mass. Some proteins were tissue-specific, but other were common, among them a highly glycosylated protein which migrated at about 55 kDa. We hypothesize that the latter, also reported in all previously studied palm species, is one of the proteins characterizing the Arecaceae family.

Storage lipids and proteins of Euterpe edulis seeds

Comparative studies on fatty acid and protein composition of the endosperm and embryo of palmito (Euterpe edulis Martius) were conducted using gas-liquid chromatography and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. On a dry weight basis, the embryo contained extremely lower amounts of lipids and proteins than did the endosperm, which was associated with the scarce lipid and protein bodies previously reported in axis and cotyledon. The fatty acid composition also exhibited differences between both tissues: (I) the fatty acid diversity was greater in embryo than in endosperm; (II) embryo and endosperm contained predominantly linoleic, palmitic, oleic and stearic acids even though the relative values were different for each tissue. As compared to other palm species, the higher fatty acid unsaturation in Euterpe edulis seed could be involved in the previously reported short longevity and recalcitrant behavior during storage. Proteins of both tissues were heterogeneous in molecular mass. Some proteins were tissue-specific, but other were common, among them a highly glycosylated protein which migrated at about 55 kDa. We hypothesize that the latter, also reported in all previously studied palm species, is one of the proteins characterizing the Arecaceae family.(AU)

Role of lipids in the early developmental stages of experimental immune diabetes induced by multiple low-dose streptozotocin.

The present work examines the role of lipids in the development of the Type 1 diabetes induced by the administration of multiple low doses of streptozotocin (STZ) in C57BL/6J mice. The study was performed before and after the onset of clear hyperglycemia, and the results were as follows. First, 6 days after the first dose of STZ, while plasma glucose and insulin levels remained similar to those observed in the control mice, plasma free fatty acid (FFA) levels were significantly increased (P < 0.05). At that time, a marked increase of triglyceride content in gastronemius muscle was accompanied by a diminished activity of pyruvate dehydrogenase complex, suggesting an impaired glucose oxidation. Furthermore, a decrease of both triglyceride content and lipoprotein lipase activity was observed in the epididymal fat tissue. Second, 12 days after the first injection of STZ, hyperglycemia was accompanied by hypertriglyceridemia, a more pronounced increase of plasma FFA, and a significant (P < 0.05) reduction of insulinemia. At this time, both the adipose tissue and the gastrocnemius muscle showed a further deterioration of all parameters mentioned after 6 days. Moreover, in the gastrocnemius muscle, an impaired nonoxidative pathway of glucose metabolism was observed [significant reduction (P < 0.05) of glycogen mass, glucose-6-phosphate content, and glycogen synthase activities] at this time point. Finally, the data suggest for the first time that, in mice, Type 1 diabetes induced by multiple low doses of STZ and enhanced lipolysis of fat pads leads to an increase in the availability of plasma FFA, which seems to play a role in the early steps of diabetes evolution.

Fish oil affects pancreatic fat storage, pyruvate dehydrogenase complex activity and insulin secretion in rats fed a sucrose-rich diet.

Rats fed a sucrose-rich diet (SRD) develop hypertriglyceridemia and a marked decline in beta cell function. The purpose of this study was to determine whether changes in triglyceride concentration and/or altered pyruvate dehydrogenase complex (PDHc) activity contribute to the beta cell dysfunction, and to analyze the effect of dietary fish oil on the altered patterns of insulin secretion and peripheral insulin resistance. Rats were fed an SRD for 210 d. One-half of the rats continued consuming the SRD until d 270. The other half received an SRD in which fish oil (FO) was partially substituted for corn oil until d 270. A group of rats was fed a control diet (CD) throughout the experiment. The islets of rats fed the SRD had a greater triglyceride concentration and lower PDHc activity than those fed the CD. Insulin secretion patterns under the stimulus of glucose, palmitate or L-arginine were impaired in SRD-fed compared with CD-fed rats. This was accompanied by peripheral insulin resistance, mild hyperglycemia, a sharp increase of plasma triglyceride and free fatty acid levels and greater epididymal and retroperitoneal fat weights. FO normalized and/or improved these variables. Our results indicate that the increased fat storage and decreased PDHc activity in the beta cells play a key role in the abnormal insulin secretion of rats chronically fed an SRD. This is consistent with the reversion of these alterations by dietary FO.

Efectos de sustratos competitivos y de la insulina sobre la captación y el destino metabólico de la glucosa en corazón perfundido de ratas dislipémicas / Effects of competitive substrates ans insulin on glucose uptake and utilization in isolated perfused hearts of dyslipemic rats

Rats chronically fed (15 weeks) a sucrose-rich diet (SRD) developed hypertriglyceridemia (hyperTg), increased plasma free fatty acids (FFA), impaired glucose homeostasis and insulin insensitivity. An increase of Tg and glycogen (Gly) in heart muscle was also observed. HyperTg with altered glucose metabolism could have profound effects on myocardial glucose utilization. To test this hypothesis male Wistar rats were fed a semi-synthetic SRD (w/w: 62.5% sucrose, 8% corn-oil, 17% protein), and the control group (CD) received the same semi-synthetic diet, except that sucrose was replaced with starch for 90 days. At that time, the hearts from these animals were isolated and perfused for 30 min in the presence or absence of insulin (30 mU/ml). Levels of the exogenous substrates were similar to those found in the plasma of the animal in vivo in both dietary groups (glucose 8.5 mM, palmitate 0.8 mM in SRD and glucose 5-5 mM, palmitate 0.3 mM in CD). In the absence of insulin glucose uptake was reduced (40%) and lactate release was increased (50%) in SRD hearts. Glucose oxidation was depressed mainly due to both, an increase of PDH kinase and a decrease of 60% of PDHa (active form of PDHc). Insulin in the perfusion medium improved only glucose uptake. The results suggest that at least two different mechanisms might contribute to insulin resistance and to impaired glucose metabolism in the perfused hearts of dyslipemic SRD fed rats: 1) reduced basal and insulin-stimulated glucose uptake and its utilization and 2) increased availability and oxidation of lipids (low PDHa and PDH kinase activities), which in turn decreased glucose uptake and utilization. Thus, this experimental model may be useful to study how impaired glucose homeostasis, increased plasma FFA and hyperTg could contribute to heart tissue malfunction.

Efectos de sustratos competitivos y de la insulina sobre la captación y el destino metabólico de la glucosa en corazón perfundido de ratas dislipémicas / Effects of competitive substrates ans insulin on glucose uptake and utilization in isolated perfused hearts of dyslipemic rats

Rats chronically fed (15 weeks) a sucrose-rich diet (SRD) developed hypertriglyceridemia (hyperTg), increased plasma free fatty acids (FFA), impaired glucose homeostasis and insulin insensitivity. An increase of Tg and glycogen (Gly) in heart muscle was also observed. HyperTg with altered glucose metabolism could have profound effects on myocardial glucose utilization. To test this hypothesis male Wistar rats were fed a semi-synthetic SRD (w/w: 62.5% sucrose, 8% corn-oil, 17% protein), and the control group (CD) received the same semi-synthetic diet, except that sucrose was replaced with starch for 90 days. At that time, the hearts from these animals were isolated and perfused for 30 min in the presence or absence of insulin (30 mU/ml). Levels of the exogenous substrates were similar to those found in the plasma of the animal in vivo in both dietary groups (glucose 8.5 mM, palmitate 0.8 mM in SRD and glucose 5-5 mM, palmitate 0.3 mM in CD). In the absence of insulin glucose uptake was reduced (40%) and lactate release was increased (50%) in SRD hearts. Glucose oxidation was depressed mainly due to both, an increase of PDH kinase and a decrease of 60% of PDHa (active form of PDHc). Insulin in the perfusion medium improved only glucose uptake. The results suggest that at least two different mechanisms might contribute to insulin resistance and to impaired glucose metabolism in the perfused hearts of dyslipemic SRD fed rats: 1) reduced basal and insulin-stimulated glucose uptake and its utilization and 2) increased availability and oxidation of lipids (low PDHa and PDH kinase activities), which in turn decreased glucose uptake and utilization. Thus, this experimental model may be useful to study how impaired glucose homeostasis, increased plasma FFA and hyperTg could contribute to heart tissue malfunction. (AU)