Einfluß der Fettzufuhr und der Fettsäurezusammensetzung auf Mast- und Schlachtleistung sowie auf Parameter des Protein- und Lipidstoffwechsels beim Schwein

Effect of dietary mono- and polyunsaturated fatty acids on the fatty acid composition of pigs' adipose tissues

In two experiments with growing-finishing pigs six different dietary fats were added to a conventional diet (control--C) to study the effects of dietary monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA) on the fatty acid composition of backfat and kidney fat at similar amounts of double bonds in feed (Exp. 1:7% pork fat--PF, 4.95% olive oil--OO, 3.17% soybean oil--SO) or a constant amount of 5% of processed fats (Exp. 2: partially hydrogenated fat--SAT, fractionated pork fats: olein--OLE, stearin--STE). Compared with the control, PUFA were only slightly increased in backfat of pigs fed PF, OLE, STE or OO, although dietary PUFA intake was up to 70% higher. With SO PUFA were significantly increased in adipose tissues, predominantly at the expense of MUFA. Consequently, a non-linear relationship was found between PUFA intake and proportion in backfat. MUFA were incorporated at the expense of SFA, therefore, adipose tissues of OO fed animals were lowest in SFA. Despite comparable amounts of double bonds in feed (Exp. 1), the degree of unsaturation measured as fat score (sum of double bonds) was in the order SO > OO > PF > C. In contrast, the proportion of SFA was C > PF = SO > OO. Regarding the decisive role of SFA for fat consistency it may be concluded that MUFA should also be considered in feeding recommendations for pigs. Furthermore, in case of a high dietary supply of MUFA, a simple index of double bonds might not be sufficiently conclusive to judge pig fat quality.

Possibility of fat addition in the rabbit diets

Baladi rabbits were fed on five-similar-experimental diets, except the replacement for starch in the 1st diet, cattle tallow in the 2nd, cotton seed oil in the 3rd, and hydrogenated palm oil in the 4th instead of 2% more wheat bran in the 5th (control) diet. All other husbandry conditions were the same for all groups of animals during the experimental period of 7 weeks. The cattle tallow in the second diet caused significant increase of feed intake, growth rate, relative weights of kidneys, lungs and heart and calcium of the tibia bone. This diet had tendency to diminish significantly blood contents of total nitrogen and cholesterol as well as vitamin A in the liver and tibia contents of silica, phosphorus and magnesium. Diet number 3 included cottonseed oil lowered blood contents of glucose, phosphorus, cholesterol and enzyme activity of glutamate oxaloacetate transaminase in the serum and specific gravity of tibia bone. On the other hand, it elevated significantly (P less than or equal to 0.01) stored vitamin A in the liver than on all other experimental diets. Feeding rabbits on diet including hydrogenated palm oil subsided liver contents of dry matter, ash and vitamin A and raised ether extract of the liver significantly. It reduced also dry matter content of the femoral muscle. Substitution for starch (instead of 2% of the diet fats or bran) increased blood content of haemoglobin and haematocrit (insignificant) but values of glucose and phosphorus as well as liver content of dry matter, content of femoral muscle of dry matter and ether extract and content of tibia bone of silica and phosphorus were significantly higher than the other experimental diets. It decreased relative weights of different organs (significantly) and liver contents of ether extract and vitamin A (insignificantly) than on control diet. It could be said that the addition of cattle tallow and cottonseed oil would be recommended to be included in rabbit diets after more studies to determine the effects of the different animal-vegetable mixtures of fats, the best ratio between the two sources of fats, the interrelationships between that mixtures and the energy of the diet, the dietary protein level, the rabbit breed and their weights and aim of the production under the seasonal variation of the weather.

[Nutritional physiology effect of dietary fats in the diet of growing pigs. 1. Effect of an isocaloric exchange of carbohydrate energy compared with fat energy on protein retention, in vitro synthesis of fat from glucose and on several blood parameters in piglets]

Three groups of male, castrated piglets of the German Landrace breed, weight range 3-30 kg, were used to study the relation between fattening performance and blood parameters when feeding rations containing different amounts of fat. The fat content of the rations was either 5% (group I), 18% (group II) or 35% (group III). Concomitantly with the increased metabolizable energy (ME) content of the ration the content of digestible protein (DP) was increased and the amount of feed reduced in order to guarantee an equal intake of ME and DP in all three groups. The digestibility of the crude nutrients and protein retention of the subjects were determined in nine subsequent trials each lasting 7 days. At a body weight of 27 kg the blood concentrations of insulin, glucose, free fatty acids, neutral lipids and cholesterol were determined at different times after feeding. In addition, an oral glucose tolerance test was made and the in-vitro synthesis of fat from glucose was measured. The apparent digestibility of fat amounted, unexpectedly, to approximately 94% on the high rat rations II and III. In all groups a significant positive relation between body weight and digestibility of the fat was determined. Despite equal daily intakes of ME in all groups, in group III daily weight gain and protein retention were 7% (p less than 0.01) and 4% (p less than 0.01) higher than in group I, respectively. Blood urea levels of group III were 67% (p less than 0.01) lower than in group I. The mean daily nitrogen retention of the three groups rose gradually from 4 g at a body weight of 5 kg to 16-17 g at a body weight of 25 kg. The feed conversion of group I was lower by 22 and 36% as compared to groups II and III, respectively. Highly significant differences were observed among either groups (p less than 0.01). It has been calculated that in group III the consumption of ME/kg weight gain was about 8% (p less than 0.05) lower than in the two other groups. According to the increased fat percentage of the rations, body protein content diminished from 17,1% in group I to 16,5 and 16% in groups II and III, respectively. Only the difference between groups I and III proved to be significant (p less than 0.05). In group I feed intake resulted in an increase in the insulin level by 55% (p less than 0.05) whereas glucose did not change significantly.(ABSTRACT TRUNCATED AT 400 WORDS)