Abstract
Crude glycerin, the main by-product of biodiesel production, can replace dietary energy sources, such as corn. The objective of this study was to evaluate the inclusion of up to 30% of crude glycerin in dry matter (DM) of the total diets, and its effects on meat quality parameters of feedlot Nellore bulls. Thirty animals (227.7 ± 23.8 kg body weight; 18 months old) were housed in individual pens and fed 5 experimental diets, containing 0, 7.5, 15, 22.5 or 30% crude glycerin (DM basis). After 103 d (21 d adaptation) animals were slaughtered and the Longissimus muscle was collected. The characteristics assessed were chemical composition, fatty acid profile, cholesterol, shear force, pH, color, water-holding capacity, cooking loss and sensory properties. The increasing inclusion of crude glycerin in the diets did not affect the chemical composition of the Longissimus muscle (P > 0.10). A quadratic effect was observed when levels of crude glycerin were increased, on the concentration of pentadecanoic, palmitoleic and eicosenoic fatty acids in meat (P < 0.05), and on the activity of the delta-9 desaturase 16 and delta-9 desaturase 18 enzymes (P < 0.05). The addition of crude glycerin increased the gamma linolenic fatty acid concentration (P < 0.01), and altered the monounsaturated fatty acids in Longissimus muscle of animals (Pquad. < 0.05). Crude glycerin decreased cholesterol content in meat (P < 0.05), and promoted higher flavor score and greasy intensity perception of the meat (P < 0.01). The inclusion of up to 30% crude glycerin in Nellore cattle bulls`diets (DM basis) improves meat cholesterol and sensory attributes, such as flavor, without affecting significantly the physical traits, the main fatty acid concentrations and the chemical composition.
Highlights
Nowadays, there is a growing interest in manipulating the carcass quality and fatty acid composition of livestock‘s meat, in order to produce meat with higher acceptance by the market, especially in terms of reduced content of saturated fatty acids (SFA), which are directly related to human diseases associated with modern life [1 – 2]
Recent studies have demonstrated that the inclusion of this by-product has effects on carcass grade [4 – 7], increases the intramuscular fat and oleic acid content [8], decreases myristic, palmitic and stearic acids in Longissimus muscle [9], increases the monounsaturated fatty acid (MUFA) content and conjugated linoleic acid content [10], decreases saturated fatty acid and increases unsaturated and odd-chain fatty acid contents [4]
The only color parameter, measured both in meat and subcutaneous fat, which was affected by the inclusion of crude glycerin in cattle diets, was the luminosity index of fat
Summary
There is a growing interest in manipulating the carcass quality and fatty acid composition of livestock‘s meat, in order to produce meat with higher acceptance by the market, especially in terms of reduced content of saturated fatty acids (SFA), which are directly related to human diseases associated with modern life [1 – 2]. Several studies were recently conducted in order to obtain healthy animal products for human consumption, keeping or increasing nutritional value of meat and not encumbering the animal production systems. Crude glycerin is a by-product of the biodiesel industry widely used in diets for ruminants, as it has great potential for replacing energetic ingredients, such as corn grain [3 – 4 – 5]. Recent studies have demonstrated that the inclusion of this by-product has effects on carcass grade [4 – 7], increases the intramuscular fat and oleic acid content [8], decreases myristic, palmitic and stearic acids in Longissimus muscle [9], increases the monounsaturated fatty acid (MUFA) content and conjugated linoleic acid content [10], decreases saturated fatty acid and increases unsaturated and odd-chain fatty acid contents [4]. In other studies the effects of crude glycerin on carcass and meat traits were neglected [11 – 12 – 13]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
