No abstract

Tannins are a group of phenolic compounds which have received a lot of attention with respect to their possible nutritional and physiological actions. Tannins can be grouped into condensed and hydrolysable tannins, widely distributed in the plant kingdom. Hydrolysable tannins are polyester of phenolic acids such as gallic acid or ellagic acid or their derivatives and D-glucose. The condensed tannins are polymer of flavan-3-ols, flavan-3,4-diols or related flavanol residues linked via carbon–carbon bonds. There is evidence that high levels of tannins could produce adverse effects in animals. These effects can be instantaneous like astringency or a bitter or unpleasant taste or can have a delayed response related to antinutritional/toxic effects

1. A trial was conducted in order to increase the docosahexaenoic acid (DHA) content in the meat of Muscovy ducks (Cairina moschata domestica L.) fed on a diet supplemented with the microalga Crypthecodinium cohnii. 2. Two diets were provided to 48 male and 48 female ducks, belonging to an Italian rural strain during the last 3 weeks of life: a maize-soybean based diet as the control diet and the same diet supplemented with 5 g/kg microalga meal. 3. Dietary treatment did not induce differences in growth performances and slaughter traits. Similarly, chemical composition, colour, pH, oxidative stability and sensory characteristics of breast muscle were not influenced by the diet. 4. A significant increase of DHA content in breast meat of ducks fed on the Crypthecodinium cohnii enriched diet was observed.

A trial was conducted to study the effect of dietary 2% soya bean oil and dietary 2% fish oil (FO) on fatty acid composition of breast meat of two different Muscovy duck (Cairina moschata domestica L.) strains. The two strains were a broiler strain selected for meat production and an unselected rural strain. Fatty acid composition of breast muscle was deeply influenced by lipid source. Dietary FO improved the long chain polyunsaturated fatty acids (LC-PUFAs) of omega 3 series content, while the content of LC-PUFAs of omega 6 series was reduced. Differences in susceptibility in lipid manipulation were found between the two groups of animals suggesting the highest capability of animals belonging to the rural strain in stocking arachidonic acid in breast muscle. As the fatty acid profile of Muscovy duck meat can be considerably modified by changing the fatty acid composition of the diet, and dietary FO represents an easy way to reach this goal, human intake of healthy n-3 LC-PUFAs could be enhanced using this enriched poultry meat, even if the influence of FO on organoleptic characteristics (i.e. off-flavours) must be evaluated.

Tannins have shown numerous biological activities and are very appreciated in food animal production, especially for their antimicrobial, antiparasitic, antioxidant, anti-inflammatory and antivirus effects. The aim of the present study was to evaluate the effect of two levels of dietary Quebracho tannin (QT) on growth and performance traits, and possible effects on intestinal parasite load in Italian White Livorno pullets. A 140-day trial was carried out on 180 35-day-old females, fed on two levels of dietary QT inclusion: 0%, 1% and 2%. Birds were reared under free-range conditions. Dietary Quebracho tannin may be used up to 1% in growing female White Livorno chickens without any adverse effects. The results observed in this study on the use of dietary QT at 2% might have not reflected the real effect on performance traits due to the initial inclusion of dietary QT at 3%. Nevertheless, by reducing QT to 2%, a progressive normalization of body weight gain, feed intake and feed conversion ratio was observed, resulting in compensatory growth. QT was demonstrated to drastically reduce fecal outputs of Nematodes eggs (Ascaridia spp. and Heterakis spp.) and Coccidia oocytes (Eimeria spp.). The inclusion of 2% produced highly dry droppings.