F. Petacchi

Effect of kind of dietary fat on the quality of milk fat from Italian Friesian cows

Four diets, supplemented with different fats of vegetable origin, were compared in a 4×4 Latin square design with eight primiparous Italian Friesian cows (two cows per cell). The four fats were: toasted full fat soy bean in diet WS; toasted full fat linseed in diet WL; calcium soap of palm oil in diet PS; and calcium soap of olive oil in diet OS. Scope of the trial was to study the effect of the four different fat sources on milk yield and composition and on the quality of milk fat in terms of safety for the consumer health, with particular attention to trans fatty acids and to conjugated linoleic acid isomers (CLA). Diet OS induced the highest milk yield (P<0.05), while diet PS gave the fattest milk (P<0.05), and the highest milk content of both saturated and medium chain fatty acids (P<0.05). Saturated to unsaturated ratio of milk fat was decreased when cows were fed diet WS (P<0.05), while the ratio was increased with cows fed on diet PS (P<0.05). With a closely similar behaviour milk CLA content was enhanced with diet WS and strongly depressed (P<0.05) with diet PS. Diet OS increased total CLA as well, probably as a consequence of the bio-hydrogenation process of large amounts of oleic acid, transformed into trans isomers of C18:1, including vaccenic acids. Full fat soy bean promoted some milk fatty acids with beneficial effects on consumer health, but calcium soap of olive oil similarly improved the fatty acid profile of milk fat, while meeting the cows’ requirements as an energy supplement.

Butyric acid glycerides in the diet of broiler chickens: effects on gut histology and carcass composition

Abstract Aim of the study was to verify the effects of butyric acid glycerides, as a supplemental ingredient in the diet, on live performance of broiler chickens and on the morphology of their small intestine, since short chain fatty acids are known as selective protection factors against intestinal microbial parasites, potent growth promoters of the gut wall tissues, also in terms of immune modulation response. An experiment was carried out on 150 Ross 308 female chickens, allotted to 5 treatments, over a 35 d ays period: the control, with soybean oil as the energy supplement, and 4 treatments with increasing amounts (0.2, 0.35, 0.5, 1% mixed feed) of a mixture of butyric acid glycerides (mono-, di- and tri-glycerides). Treated animals showed a higher live weight at slaughtering (P<0.05) with a better feed conversion rate. The carcase characteristics were not influenced, but the small intestine wall resulted slightly modified with shorter villi, longer microvilli (P<0.01) and larger crypts depth in jejunum (P<0.01), only with lowest concentration of the supplement (0.2%). It is concluded that butyric acid glycerides are an efficient supplement to broilers’ diets, deserving particular attention as a possible alternative to antimicrobial drugs, which have been banned in Europe.

Upgrading the lipid fraction of foods of animal origin by dietary means: rumen activity and presence of trans fatty acids and CLA in milk and meat

Abstract The recent literature dealing with the effect of the diet on the quality of milk and meat fat is reviewed. Some aspects of the rumen metabolism of lipids are dealt with: lipolysis, bio-hydrogenation, synthesis of microbial fatty acids and inhibition mechanisms on fermentation. Firstly, the influence of forage is considered. Pasture is the best forage, better if high hill pasture, as compared to hay and silage: short chain fatty acids (SCFA) (shorter than C10) are increased, medium chain fatty acids (MCFA) (C12 through C16) are decreased, oleic (OA), linoleic (LA) and linolenic (LNA) acids are increased and so are the conjugated linoleic acid pool of isomers (CLA) and n-3 polyunsaturated fatty acids (n-3 PUFA). Secondly, the energy supplementation of diets with fats is looked at. Animal fats depress milk yield and SCFA, while OA is increased because of the enhanced activity of mammary ∆9 desaturase. Fish oil depresses milk yield as well, but promotes CLA and n-3 PUFA. If animal fats are protected against rumen bacteria, milk yield and milk fat depression are avoided. Vegetable fats are richer in unsaturated fatty acids (UFA), thus more susceptible to the rumen bio-hydrogenation. As calcium soaps or inside whole seeds, plant fats are protected and CLA is increased. CLA is an important component of fat. In ruminants it comes from the desaturation of vaccenic acid (VA) both in rumen and udder; and the yield of VA depends on the diet quality. In conclusion, simple directions are given on how to improve the quality of animal fat by dietary means, without affecting yield.

Effect of tannin supplementation on nitrogen digestibility and retention in growing pigs.

Abstract Two levels (0.25% and 0.5%) of water soluble chestnut tannin were added to the diet of growing pigs in a 40 days feeding trial, from the average body weight of 76kg up to about 110kg. As expected, a significant depression of the apparent digestibility of both dietary dry matter and nitrogen was recorded with level 0.5%, but the decrease of retained nitrogen was not statistically significant, due to the higher dietary nitrogen. It is concluded that the present preliminary study showed that a concentration of 250g tannin per 100kg mixed feed does not appreciably influence the animals’ performance. The aspect of a possible beneficial effect on the gut microflora deserves further studies.

Use of a citrus by-product in broilers diets

Riassunto Impiego di un sottoprodotto del pastazzo di agrumi nelle diete per broiler. 160 broiler ibridi Ross 308 sono stati alimentati con 4 diete integrate con differenti percentuali di un sottoprodotto del pastazzo di agrumi ricco in flavonoidi, ottenuto dalla lavorazione delle arance rosse per la produzione di succhi di frutta. I migliori accrescimenti si sono avuti con il prodotto secco all’1%, sia pur con il peggior indice di conversione (p<0.05). Le analisi relative al contenuto di IgM e IgG nel sangue hanno mostrato una maggiore sollecitazione del sistema immunitario dei soggetti alimentati con una più elevata concentrazione di flavonoidi nella dieta, anche se non in maniera statisticamente significativa.

Influence of CLA supplementation on the lipid quality of rabbit meat

Riassunto Effetti dell’integrazione di CLA sulla qualità dei lipidi della carne di coniglio. Per la prova sono stati utilizzati 24 conigli, ibridi californiani, alimentati con 3 diete diversificate per quantità e qualità della fonte lipidica: la dieta di controllo conteneva olio di soia all’1%, mentre le altre sono state integrate rispettivamente con l’1 ed il 2% di un olio di girasole arricchito industrialmente di Acido Linoleico Coniugato (CLA). Le diete in esame hanno mostrato una buona appetibilità e gli animali in prova non hanno evidenziato alcuna patologia. Le carni ottenute hanno presentato un arricchimento in CLA, in maniera del tutto paragonabile alla percentuale di inclusione di tale acido grasso nella dieta.

Development of Conjugated Linoleic Acid and C18:1 content during in vitro rumen fermentation of dried and green forage

Milk and dairy products contain important compounds which are strongly related to the kind and quality of feeds. Milk fat is a source of potential anticarcinogens as the conjugated linoleic acid (CLA) isomers. Cis9, trans11 CLA is the major isomer, named “rumenic acid” (RA), because is synthesised during rumen fermentation by Butyrivibrio fibrisolvens that isomerise linoleic acid to conjugated isomers. Next step of biohydrogenation is the reduction to trans11 C18:1 (vaccenic acid, VA). During rumen fermentation, also, trans C18:1 fatty acids can be synthesised as a result of polyunsaturated fatty acids reduction, some of them responsible for milk fat depression in dairy cows.........

Effect of chestnut tannin in the diet of lactating ewes on milk and cheese quality

Abstract A commercial product consisting of pure soluble tannins extracted from chestnut wood was introduced into the diet of lactating ewes at pasture, at the level of 20 g / head / day in the concentrate mixed feed. The supplementation with tannins did not exert any influence on milk yield and on lactose and fat content of milk, but induced an increase in milk protein yield, apparently in heat coagulable proteins. This is maybe due to an increase of the rumen undegradable fraction of dietary proteins. The somatic cells count and the bacterial load of milk were not affected as well. Further studies are needed to confirm these important results, in order to optimize the nitrogen metabolic balance of ruminant animals, among the other advantages.

Mixtures of mono-, di- and tri-glycerides as energy supplements to broilers’ diets

Abstract Mixtures of mono-, di- and tri-glycerides from olive oil (MDT) were added to: palm oil (PO), olive oil (OO), soybean oil (SO), free fatty acids from palm oil (PFA), free fatty acids from olive oil (OFA). The compound mixtures were used as energy supplements in the diets of broiler chickens in comparison with plain SO and plain animal fat (AF). Two hundred and ten birds were randomly allotted to 7 dietary treatments with the diverse oil sources: 6 birds per cage, 5 cages per treatment. The effects of the treatments on growth rates, feed/gain ratios and acidic composition of abdominal fat of hybrid Ross 308 female chickens were studied. The animals were slaughtered at the end of the trial, at day 35. The breast meat quality was then evaluated by a panel of 15 trained members and analysed for shelf life duration. The AF treatment gave the highest weight gain, but only in the first week. MDT + OO (50/50) resulted the best combination, with slight, non significant, better performances and a decidedly better quality in terms of acidic composition of abdominal fat, taste and juiciness of breast meat and shelf life.