Small ruminant meat with innovative feed resources

The aptitude of ruminants to use feed without competing with human resources besides their capacity to take advantage of feed of low nutritional value and exploit poorly productive and marginal areas represent a great benefit in terms of sustainability. Small ruminant, namely sheep and goat, represent a great part of ruminant sector (56 %). The husbandry of these species has enormous growth potential, particularly in developing countries, where there will be the greatest growth of the world population in the next years. Moreover, given the favorable commercial characteristics observed in both sheep and goat carcasses, the production of their meat is believed to increase and acquire a significant share of international meat trade in short to medium time. Within this framework, I first analyzed sheep and goat carcass characteristics and meat quality as well as the factors that can influence them by means of a literature review on the topic. The main intrinsic and extrinsic factors that may affect animal performances and productivity were examined, also presenting a comparison among different breeds. Moreover, the review provides a description of meat physical characteristics, i.e. pH, shear force, color and water holding capacity besides chemical and nutritional characteristics, i.e. protein, fat, minerals and vitamins. Small ruminant meat is a valuable source of proteins and contains bioactive compounds such as taurine, carnosine, coenzyme Q, creatine, and creatinine. It provides essential fatty acids such as α-linolenic, shows higher levels of conjugated linoleic acids and represents an important source of minerals and vitamins with particular regards to iron and Vitamin B12, which is synthesized by ruminal bacteria. Meat quality depends upon overall carcass characteristic but is strictly related to the structural and biochemical characteristics of muscles. Among intrinsic and extrinsic factors that can influence them, the feeding regime is recognized as a major one. In this context, aiming to enhance an innovative approach to a circular bio-economy model, an experiment was conducted in order to investigate the influence of dietary inclusion of cardoon meal on the sensory quality of lamb meat aiming to detect those volatile compounds mainly involved in its final flavour and odour. Indeed, cardoon meal is a by-product composed of partially defatted seed of the cultivated cardoon (Cynara cardunculus var. altilis) that has been proposed as an innovative feed for ruminants due to its valuable content of fibre, protein, amino acids, unsaturated fatty acids and bioactive compounds. Results showed that the substitution of alfalfa with cardoon meal slightly influenced lambs fat odour. Cardoon inclusion reduced the “animal/barnyard” odour perceived in the kidney fat of alfalfa-fed lambs, which could be linked with the aromatic compound p-cresol detected only in that group. Regarding the other volatiles that are considered to be determinants of the characteristic lamb flavour (i.e. BCFAs, skatole, indole), both diets were characterized by their absence or a moderate to low level detection. Another experiment was carried out to investigate the effect of dietary inclusion of different tannin extracts on lamb meat volatile compounds and flavour. Tannins, widespread among plants commonly consumed by ruminants, are able to form complexes with proteins, limiting their ruminal degradation and thus the synthesis of some odour-active compounds that may be considered as unpleasant. The extracts were: mimosa (A. mearnsii; condensed tannins), chestnut (C. sativa; hydrolysable ellagitannis) and tara (C. spinose; hydrolysable gallotannins). Results clearly demonstrated that tannins reduced pastoral odour in perirenal fat of lambs the meat of which was characterized by a very low perception of this attribute. It was assumed that p-cresol and 8-methylnonanoic acid mostly contributed to pastoral odour expression in the diet without tannins.