Ácidos graxos como marcadores biológicos da ingestão de gorduras

Odd-chain fatty acids as an alternative method to predict ruminal microbial nitrogen flow of feedlot Nellore steers fed grain-based diets supplemented with different nitrogen sources

This study aimed to evaluate the use of total odd-chain fatty acids (OCFA) as a marker to estimate microbial nitrogen flow (MicN) and calculate the efficiency of microbial nitrogen synthesis (EMNS) in Nellore steers fed high-concentrate diets supplemented with different nitrogen supplements (NS). Ruminally and duodenally cannulated Nellore steers (n = 6; 354 ± 12 kg) were used in a 6 × 6 repeated switchback design balanced for residual effects. Treatments were arranged in a 3 × 3 factorial of three nitrogen (N) supplements (urea plus soybean meal; corn gluten meal; dried distillers' grains plus solubles) and three microbial markers (OCFA; double-labeled urea, 15N; microbial nucleic acid bases, MNAB). The total mixed ration was composed of fresh chopped sugarcane as the forage source in an 83:17 concentrate: forage ratio (dry matter basis). Linear regression was used to develop predictions of MicN from OCFA using 15N and MNAB as response variables. Microbial N flow was underestimated by the MNAB marker compared to 15N. Neither NS nor their respective interactions with the marker methods (MM) affected MicN or EMNS (P > 0.05). However, MicN was different for 15N and MNAB (P > 0.001 for both treatments). Marker methods affected EMNS in all energetic bases (total digestible carbohydrates P < 0.001; rumen-fermentable carbohydrates P < 0.001; organic matter truly degradable in the rumen P < 0.001). Equations that utilized OCFA as a regressor to predict MicN under different MM resulted in good fits of the data as observed by the coefficient of determination (R2; 15N = 0.78; MNAB = 0.69). Microbial N flow estimated from OCFA was overpredicted (15N by 7.46%; MNAB by 4.30%) compared with observed values. The OCFA model presented a small slope bias when methodological validation was applied (15N = 0.96%; MNAB = 3.90%), ensuring reliability of the proposed alternative method. Based on the conditions of this experiment, OCFA may be a suitable alternative to other methods that quantify MicN under different dietary conditions.

ω-3 in meat products: benefits and effects on lipid oxidative stability

Although ω-3 intake has been associated with numerous health benefits, its addition to certain food matrices, and in particular meat products, may involve various technological barriers influencing the final quality of the products. Lipid oxidation must be highlighted due to the modification of both the sensory characteristics and the shelf-life of meat products. In order to reduce the impact of chemical changes and promote oxidative stability, the use of natural antioxidants has gained ground owing to the health and safety advantages linked to its effectiveness at reducing lipid oxidation. Many natural compounds have also been successfully tested in animal feed, in order to protect the raw meat materials and reduce the risk of lipid oxidation in processed products. This review aims to address the challenges and advantages of the incorporation of ω-3 fatty acids in raw meat materials and processed meat products, and to describe the use of different compounds to enhance lipid oxidative stability. © 2015 Society of Chemical Industry.

Reporting of trans-fat on labels of Brazilian food products

Objective

The present study investigated how trans-fat is reported on the packaging of foods sold in a Brazilian supermarket.

Design

The present descriptive, cross-sectional study analysed the ingredient list, nutrition facts label and claims of no trans-fat on the packaging.

Setting

A large supermarket in Florianópolis, Brazil.

Subjects

All food products available at the supermarket.

Results

Of the 2327 study products, more than half had components containing trans-fat in the ingredient list, especially hydrogenated vegetable fat and its alternative names. A small percentage of food products reported some trans-fat content on the nutrition facts label and roughly a quarter of the food products claimed to contain no trans-fat on the front of the packaging. There was very low agreement among the trans-fat content reported in the nutrition facts label, claims of no trans-fat made on the packaging and the ingredient list.

Conclusions

There was low agreement among the different ways of reporting trans-fat, suggesting that it is not possible to rely on the nutrition facts label or no trans-fat claims printed on the packaging of Brazilian food products. Hence, the Brazilian legislation on food labels needs to change to improve the reliability of food labels and to help control the trans-fat intake of the population.