Dietary citrus pulp reduces lipid oxidation in lamb meat

Vitamin E is the major contributor to the antioxidant capacity in lambs fed whole dried citrus pulp

“…Citrus phenolic compounds possess antioxidant activities and their intake with the diet has been suggested to increase the antioxidant capacity of animal tissues. In the light of this, we recently demonstrated that the oxidative stability of the meat from the same lambs used in this study was increased by feeding the CIT diet and we attributed this effect to the presence of flavonoids in the DCP (Inserra et al, 2014). However, it has been reported that the possible mechanisms explaining the antioxidant effects of dietary citrus flavonoids are far from being clear and several authors suggest that their antioxidant effects in vivo are likely to be overestimated (Khan et al, 2014).…”

“…Once again the fact that, in the present study, animals were not subjected to conditions promoting lipid peroxidation could partially explain why an effect of feeding CP on lipid oxidation was not observed in liver, plasma and muscle collected from the animals and immediately stored at −80°C without being subjected to further oxidative stresses until analyses. Nevertheless, using the same animals of the present experiment, Inserra et al (2014) demonstrated that the CIT diet reduced the susceptibility to lipid oxidation of muscle, which could be appreciated when meat was stored for 6 days at 4°C. Therefore, in the present study, we also assessed the resistance of muscle lipids to oxidation by incubating muscle homogenates in the presence of Fe/Asc as catalyst for inducing lipid peroxidation (Monahan et al, 2005).…”

“…The samples were mixed and incubated at 80°C for 90 min in a water bath, after which the absorbance was measured at 532 nm. The TBARS assay in liver and muscle was performed following the same procedure described by Inserra et al (2014).…”

“…Citrus fruits have received special attention for their content of phenolic compounds and it has been shown that citrus by-products are richer in polyphenols than the portions consumed by humans (Balasundram et al, 2006;Nogata et al, 2006). Recently, we have demonstrated that feeding lambs with concentrate-based diets including up to 35% DCP increased the resistance of muscle lipids and proteins to oxidative deterioration Inserra et al, 2014). The results of these studies were discussed in the light of the possible antioxidant effects of the polyphenols present in CP, in agreement with results provided by studies in which sheep were fed with either citrus extracts or with purified citrus flavonoids (Gladine et al, 2007c;Bodas et al, 2012).…”

“…Moreover, possible effects of antioxidants present in the DCP might be exerted in the gastrointestinal tract of the animals, leading to a reduction of oxidative damages at the level of the intestine (Lindley et al, 1994). To test these hypotheses, we used the same lambs from the experiment of Inserra et al (2014) and we measured the antioxidant status of the lipophilic and hydrophilic fractions, as well as the extent of lipid oxidation, in the liver, blood plasma and muscle. Furthermore, lipid oxidation was measured in the small intestine and in the faeces.…”