Articles | Veterinární medicína | Agricultural Journals

Due to consumer demand, in recent years considerable attention has been focused on the use of natural compounds in animal feed. The aim of this study was to evaluate the effect of dietary natural extract from Lippia citriodora (commonly named "limoncina"), titrated in verbascoside, on quality, measured as oxidative stability, fatty acid composition, alpha-tocopherol and retinol content and sensory traits of rabbit meat. Forty-five New Zealand white rabbits were randomly assigned to three age- and body-weight-balanced feeding groups of 15 animals each in which a conventional pelleted diet (CON) was supplemented with 1 or 2 kg t⁻¹ (low natural-extract (LNE) and high natural-extract (HNE) groups, respectively) of Lippia citriodora extract for 55 days. No influence on carcass characteristics and the chemical composition of meat was observed. A trend for a positive effect on alpha-tocopherol tissue content (P = 0.07) and on thiobarbituric reactive substance (TBARS) values was observed (P = 0.063) in Longissimus Lumborum muscle from the HNE group. The fatty acid profile of the meat was affected by dietary treatment with a significant decrease (P = 0.001) in saturated fatty acids and an increase (P = 0.01) in polyunsaturated fatty acids in both treated groups compared to the CON group. The supplementation with natural extract at the highest dosage improved the tenderness and juiciness of meat, highlighting a better consistency than CON and LNE groups. In conclusion, this study shows that the natural extract used has the potential to improve rabbit meat in order to produce functional food, without altering the chemical and physical characteristics of meat.

Milk yield and milk qualitative parameters were evaluated in Lacaune ewes on a diet supplemented with extruded linseed, verbascoside and vitamin E. A 98 d-trial was conducted on 44 ewes and started 40±2 d post partum. The animals were divided into four homogeneous groups of eleven animals each; one control group (CON) without extruded linseed and dietary supplements, and the diet of the other three experimental groups was enhanced with extruded linseed (L group), extruded linseed-verbascoside (LVB group), and extruded linseed-verbascoside-vitamin E (LVBE group). All animals individually received an isoenergetic diet, consisting of 700 g concentrated feed and meadow hay ad libitum. Body weight, body condition score, milk yield and milk qualitative parameters were assessed. LVB and LVBE groups resulted in a significant improvement (P<0·05) in milk yield due to the verbascoside supplementation. The extruded linseed supplementation L, LVB and LVBE groups produced a milk fat increase and a better milk fatty acid profile in terms of a higher monounsaturated fatty acid (MUFA), polyunsaturated fatty acid (PUFA) and conjugated linoleic acid (CLA) content and a reduced saturated fatty acid (SFA) content, a lowern-6/n-3 ratio and atherogenic and thrombogenic index. The dietary verbascoside supplementation in the LVB and LVBE group resulted in a better milk quality due to the low cholesterol level and higher vitamin A and E contents, in addition to an increased oxidative stability highlighted by the lower thiobarbituric acid reactive substances (TBARS) level. Thus, the addition of extruded linseed and verbascoside supplements improved milk yield and quality both from a chemical and nutritive point of view.

Three different dietary doses of Lippia citriodora natural extract were tested in order to verify their effect on productive performance and the meat quality of intensively-reared hare (Lepus europaeus Pall.). The 240 day-trial was conducted on 20 male hares, divided into 4 homogeneous groups of 5 animals each. A control group received a basal diet without any supplementation, and the other three experimental groups received a natural extract of Lippia citriodora, titrated in verbascoside, in the following amounts: 1 g, 1.5 g and 2 g of natural extract/kg feed in the low (LNE), medium (MNE), and high natural extract (HNE) groups, respectively. Natural extract enhanced the quality of the meat: there was a significant decrease (P<0.05) in saturated fatty acids and a significant increase (P<0.05) in mono- and poly-unsaturated fatty acids. The oxidative stability of the meat improved, thus highlighting a possible link between the decrease (P<0.05) in TBARS values and an increase (P<0.05) in lipid vitamin content. The cholesterol content of the meat decreased markedly (P<0.01) after the dietary verbascoside treatment, thus improving the health benefits of the meat. These results clearly show the important role of Lippia citriodora extract, titrated in verbascoside, in improving the quality of the meat of intensively-reared hares. In addition the present paper underlines how the use of natural antioxidant in the animal feeding system may provide healthier and low-oxidized products to the final consumer.