EVALUATION OF THE ERYTHROCYTE MEMBRANE LIPIDOME PROFILE IN GROWING LAMB BEFORE AND AFTER SUPPLEMENTATION WITH HEMPSEED CAKE

Recently, there has been a growing interest on hemp (Cannabis Sativa L.) due to the plantʼs pharmaceuticals properties that offer a wide variety of applications, and research studies are currently focusing on the investigation of its properties on human and animal nutrition. Hemp can be a source of amino acids as well as of essential fatty acids and it can be used as a supplement in feed. In dairy ruminant nutrition, hempseed and its derivatives (oil, cake and meal) has been given as a dietary supplement to sheep and ewes in the past [1], however a systematic study to evaluate the possible changes on the erythrocytes' membranes of the animal after such supplementation has not yet been conducted. The aim of this study was to compare the lipidomic profile of the erythrocytesʼ membranes of growing lambs with and without the supplementation of hempseed cake – HSC, using methods of lipidomic analysis. This study was conducted at a farm located in the Abruzzo region, Italy. For the present study, 46 Bergamasca lambs (20 males, 26 females) with an age of 45 days, initial body weight (BW) of 18k (min=15,2, max=20.8) and a typical Body Condition Score (BCS) of 3/5 were selected and equally divided in 2 groups: control (CTR) and experimental group (HSC group). All animals received a total mixed ration diet (TMR), formulated to support their growing needs. CTR lambs were given TMR with soybean and by-products of soybean meal as the main protein source, while a 12% DM of these feed was replaced by hempseed cake in the HSC group. Hay and water were offered to lambs ad libitum. Whole blood samples in EDTA were collected from each animal after 60 days of receiving the two different diets. The erythrocytesʼ membranes was then isolated and by Gas-Chromatography a group of 10 fatty acids (FA), specifically: saturated (SFA: stearic, palmitic), mono-unsaturated (MUFA: palmitoleic, oleic, vaccenic), polyunsaturated FA ω-6 (PUFA-ω6: linoleic, dihomo-gamma-linolenic [DGLA], arachidonic [ARA]) and PUFA ω-3 (eicosapentaenoic [EPA], docosahexaenoic [DHA]) was determined, along with additional lipid parameters (SFA/MUFA, SFA/PUFA, ω6/ω3, PUFA balance, unsaturation [UI] and peroxidation [PI] indexes). Between the two groups no differences were observed in the SFA concentration, however there was a significant decrease in the levels of oleic acid (p=0.01) in HSC group, that lead to the decreased levels of the total MUFA (p=0.0046). On the other hand, at the HSC group there was an increase of the concentration of the omega-3 (p=0.0046) as well as the omega-6 (p=0.0021) resulting in the increase of the total PUFA (p=0.0021). Specifically, the levels of the omega-6 fatty acid ARA were significantly higher (p=0.0001) and both of the omega-3 EPA and DHA were in increased levels as well (p=0.0028 equally). Equally significant (p = 0.0003) were the decrease of the triene/tetraene ratio (ω6/ω3) and the increase of PUFA balance ω3/(ω3+ω6) for the HSC enriched diet. The UI and PI were found in significantly higher levels for the HSC lambs (p=0.0001 and p<0.0001 respectively). In conclusion, an evaluation of the lipidic profile of ovine erythrocytes has been occurred for the first time and our data indicate that a diet rich in HC can result in increased levels of PUFA, with a specific importance on the increase of the essential fatty acids EPA and DHA that are generally known to play a beneficial role in cell functions.