Lipids have been used in ruminant feed to replace high amounts of grain for increasing the diet energy density, performance and meat quality. This study evaluated the qualitative characteristics of meat from feedlot heifers fed with sources of lipid supplements. Twenty-one crossbred heifers (¼Nelore × ¼Santa Gertrudis × ½Braunvieh) were used. Each heifer received 60 % forage with a base of corn silage and 40 % concentrate, resulting in 5.8 % lipid content in the total diet. The following sources of lipids were used: soybeans, protected fat and soybean oil. There were no differences on physical characteristics of meat samples from heifers fed with the lipid sources. Soybeans increased the concentration of linoleic acid, content of polyunsaturated fatty acid and activity of the Δ 9 -desaturase C16 enzyme in the Longissimus muscle. The use of soybean oil in the diet increased the oleic acid, monounsaturated fatty acid, total cis-and trans-fatty acids (C18:0) and the activity of the Δ 9 -desaturase C16 enzyme in the subcutaneous fat. Diets with soybean grain had greater deposition of linoleic and linolenic acids than diets with fat protected and greater presence of these essential fatty acids are associated to a better composition and meat quality.

The objective of this study was to evaluate the effects of sources of soybean oil [ground soybean (GS), soybean oil (SO) and calcium salts of soybean oil (CS)] on DM intake (DMI), ingestive behaviour and average daily gain (ADG) of heifers grazing marandu palisadegrass (Brachiaria brizantha cv. Marandu) supplemented in two frequencies [daily and 3 days a week (Monday, Wednesday and Friday -MWF)]. The experiment was conducted from July until November of 2007. Forty-two crossbred heifers (1/4 Nellore · 1/4 Santa Gertrudis · 1/2 Braunvieh), 17-months old and 297.1 kg AE 30.5 BW AE s.e.m., were used. Supplements were offered at 0.75% BW.day. Treatments were allocated in a completely randomised design and distributed in a factorial arrangement (3 · 2 -SO from three different sources and two supplementation frequencies). Total DMI was greater in August and October (2.2 kg DM/kg BW) than in November (1.5 kg DM/kg BW). There was an effect of SO source on total DM, herbage and nutrients intake, but no effects of supplementation frequency. The animals supplemented with SO had greater DMI (P < 0.05) than the ones fed GS and CS. Average daily gain (0.580 g) was not affected by supplement sources or feeding frequency. Therefore, GS and CS are more efficient supplements. Supplementation frequency altered grazing time differently according to source. The MWF treatment resulted in a decreased grazing time when GS and SO were fed. However, in days when supplements were not offered, grazing time was increased for GS and CS. It was concluded that a decreased frequency of supplementation may be implemented without effect on weight gain and will reduce labour and machinery costs.

-The objective of this study was to evaluate the effect of different lipid sources on nutrient intake, performance, development and carcass characteristics of heifers raised in confinement. Twenty-one crossbreed heifers (Nellore × Santa Gertrudis × Braunvieh) received 600 g/kg forage composed of corn silage and 400 g/kg concentrate with a 58.0 g/kg fat content in the total diet. The following lipid sources were used: soybeans, protected fat (Megalac-E ® ) and soybean oil. The experimental design was completely randomized, with three treatments and seven replicates, and the means were compared by the Tukey test at 5%. The protected fat diet resulted in a greater intake of dry matter (8.80 kg/d) when compared with the other diets. The animals that were fed the protected fat diet had a higher average daily weight gain and slaughter weight.Feed conversion and protein efficiency rate were not influenced by lipid sources. Carcass yield was not influenced by the different diets.

It is important to know the nutritional composition of the fish, especially the nutritional value of the commercial cuts most consumed by the population. The aimed of this study was to evaluate the chemical composition of commercial tambaqui (Colossoma macropomum) cuts in different classes of body weight. The sample collections were carried out in processing units in two municipalities in the state of Rondônia, Brazil.  The Data on 200 fish were recorded, with weight ranging from 1000 to 4700 g. Five classes of body weight were established, class 1 - below 1.2 kg; class 2 - from 1.21 to 1.8 kg; class 3 - from 1.81 to 2.4 kg; class 4 - from 2.41 to 3.5 kg; class 5 - over 3.5kg. The commercial cuts were lyophilized and intended for chemical analysis. The Kruskal-Wallis test (α=0.05) was used to compare the averages. The composition of commercial cuts was different in weight classes (p<0.05). The filet presented more representative values in mineral matter, crude protein and total lipids and lower humidity for class 4 (from 2.41 to 3.5 kg). The classes 1 and 5 (below 1.2 and over 3.5 kg) were different (p<0.05) in relation to the lipid and moisture content in the commercial filet and rib cuts. The tambaqui steak in class 4 have a higher lipid content compared to the average of the lightest body weight classes, 9.99 vs 4.50%, in addition to having a lower moisture content (p<0.05). The tambaqui band was different (p<0.05) in relation to nutritional components between body weight classes, with class 4 being richer in minerals, crude protein and lipids in dry matter. Therefore, the class 4 was the most efficient (p<0.05) for production and commercialization. Because the tambaquis with body weight between 2.4 to 3.5 kg stood out in relation to the nutritional components in the different commercial cuts.

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Over the productive cycle, the performance of cattle in grazing systems may be compromised, and feed supplementation is a strategy to establish nutritional balance and maximise the performance of grazing animals. The objective of this study was to evaluate the effect of different supplementation frequencies (i.e. daily supplementation (DS) versus Monday, Wednesday and Friday (MWF)) with different forms of soybean oil (i.e. soybean grain (SG), soybean oil (SO) and rumen-protected fat (RPF)) on the nutrient digestion and rumen fermentation of heifers grazing Brachiaria brizantha cv. Marandu pastures. Twelve crossbred heifers (1/4 Nellore × 1/4 Santa Gertrudis × 1/2 Braunvieh) with an initial bodyweight of 236.3 ± 27.6 kg were distributed in a completely randomised design with a factorial arrangement 3 × 2 (three diets and two supplementation frequencies). There was no interaction among the SO form or supplementation frequency on dry matter intake and dry matter digestibility (P > 0.05). The animals supplemented with SG exhibited lower nitrogen intake and absorption compared with animals that were fed SO (P < 0.05). The efficiency of microbial synthesis was not influenced by the diet or supplementation frequency (P > 0.05). Forms of SO affected the rumen pH; animals fed SO showed pH values similar to those of animals receiving SG but lower values than animals fed RPF (P < 0.05). Animals supplemented with DS exhibited higher levels of rumen ammonia nitrogen relative to those supplemented MWF. The reduction of supplementation frequency (from DS to MWF k) in our experimental conditions can be used to increase the efficiency of pasture utilisation without effects in fermentation activity of the rumen microbial population. Supplementation with SO is a strategy to increase propionic acid concentration and reduce A : P ratio, which is an indicator of improvement of the efficiency of the ruminal energy utilisation.

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