Effect of pre- and postpartum supplementation with lipid-encapsulated conjugated linoleic acid on reproductive performance and the growth hormone-insulin-like growth factor-I axis in multiparous high-producing dairy cows.

The objective of the study was to evaluate the effect of prepartum and postpartum (PP) supplementation with 2 isomers of conjugated linoleic acid (CLA) on reproductive parameters and some related metabolic factors in dairy cows. High-producing, multiparous Holstein Friesian cows (n = 60) were allotted to 3 treatment groups: the CLA1 group (n = 20) was supplemented with 70 g of lipid-encapsulated CLA providing 7 g each of cis-9,trans-11 and trans-10,cis-12 CLA from d 21 (d 21) before expected calving until d 7 after artificial insemination (AI), that is, until 77 to 91 d PP; the CLA2 group (n = 20) was supplemented with the same amount of CLA beginning at calving until d 7 after AI; and the control group (n = 20) received an isocaloric, isonitrogenous, and isolipidic diet. Blood samples were taken weekly to measure glucose, insulin, insulin-like growth factor-I (IGF-I), and leptin. Liver biopsy was performed in 10 cows per group for growth hormone receptor 1A and IGF-I mRNA analyses. At d 49 to 63 PP, ovulation was synchronized with the Pre-Synch protocol followed by fixed-time AI. Milk progesterone was monitored from calving until d 35 post-AI. Cows returning to estrus following AI were inseminated. Supplementation with CLA before calving improved the recovery of plasma leptin levels in the early PP period (from the day of calving until wk 3 PP; treatment effect). Later PP (wk 5), plasma IGF-I, and leptin remained significantly higher in both CLA1 and CLA2 groups compared with control, although hepatocellular IGF-I mRNA was not different among groups. Plasma IGF-I levels remained higher in both CLA-treated groups on the day of AI. Growth hormone receptor 1A mRNA levels in hepatic tissue decreased in all groups, reaching a nadir in the first week PP. Days to first PP ovulation did not differ between groups; however, both supplemented groups conceived earlier compared with control (d 97 ± 19, d 97 ± 23, and d 113 ± 30 for CLA1, CLA2, and control, respectively). Plasma progesterone concentration was higher in both supplemented groups on d 2 to 5 following the synchronized ovulation than in controls. We concluded that CLA supplementation around calving alters PP metabolic signals as reflected by higher plasma leptin and IGF-I levels. Conjugated linoleic acid stimulated early luteal function and reduced the PP interval to conception.

Effect of a dietary supplementation with linseed oil and selenium to growing rabbits on their productive performances, carcass traits and fresh and cooked meat quality.

The present experiment tested a dietary supplementation with linseed oil and selenium to growing rabbits. The basal diet (B) contained 3% sunflower oil, while it was substituted with 3% linseed oil in the experimental feed (S). The selenium (Se) content of the two diets was 0.10 vs. 0.46 mg/kg. Rabbits were fed with B diet from the age of 18 days. One group was fed with the B diet until 11 weeks of age (group B), whereas the experimental groups were fed with S diet for 1, 2, 3 or 4 weeks (groups S1, S2, S3 and S4, respectively), before slaughtering (11 weeks of age). Live performance and carcass traits of rabbits, fatty acid (FA) profile and selenium content of their hind leg (HL) and Longissimus thoracis et lumborum (LTL) meat were considered in this study. In addition, the effect of two different cooking methods on the nutritional value of the enriched HL meat was also assessed. The tested dietary supplementation only minimally affected the live performance and carcass traits of rabbits. The S supplementation significantly reduced the Σ n-6 FA and increased the Σ n-3 FA of the HL meat and LTL meat, compared to the B diet (p < 0.001); thus, n-6/n-3 ratio was improved (p < 0.001). In addition, HL meat and LTL meat of S fed rabbits were significantly enriched in Se reaching a twofold increase in both meat cuts (p < 0.01). Therefore, the S supplementation improved the functional value of the rabbit meat. The heat treatment affected cooking loss, Se and vitamin E contents as well as the oxidative status of the HL meat (p < 0.001), with the different cooking methods providing different results. In addition, even if the beneficial C20:5 n-3 and C22:6 n-3 decreased with cooking, the n-6/n-3 ratio remained unaffected.

Effect of pre- and post-partum supplementation with lipid-encapsulated conjugated linoleic acid on milk yield and metabolic status in multiparous high-producing dairy cows.

We evaluated the lactation performance, liver lipid content and plasma metabolites indicating the energy balance of dairy cows supplemented with conjugated linoleic acid (CLA) pre- and post-partum (PP) vs. only PP. A total of 60 cows were divided into three groups (n = 20). Daily diet of cows was supplemented with 14 g of CLA (7 g cis-9, trans-11 and 7 g trans-10, cis-12 isomers) from week 3 before the expected date of calving (group CLA1), or from the day of calving (group CLA2) until 77-91 days PP. Control cows were fed an isocaloric, isonitrogenous and isolipidic diet without CLA. Between week 3 and week 6 PP, the milk yield of cows in both CLA-treated groups was approximately 4.5 kg higher (p < 0.05) than in control. Milk fat concentrations decreased from week 3 and were lower in both CLA groups than in control (p < 0.01). Body condition score loss was lower (p < 0.05) in the CLA1 than in the control group on week 5 PP. By week 11 PP, the body condition of both CLA1 and CLA2 groups exceeded that of control. Plasma non-esterified fatty acid was lower in CLA1 compared to CLA2 and control during the early PP period (p < 0.05), while this difference faded away by the late PP period. Beta-hydroxybutyrate (BHBA) increased rapidly in all groups following calving. In CLA1 group, it began to decrease sooner than in CLA2 and control. The prevalence of subclinical ketosis (BHBA > 1.2 mm) was lower in CLA1 group than in CLA2 and control (p < 0.05). Liver biopsy analyses showed that CLA1 treatment decreased (p < 0.05) the total lipid content of liver compared to control at week 5 after calving. Our results show that CLA supplementation is more efficient in alleviating body mass mobilization and decreasing the incidence of subclinical ketosis when applied as early as 3 weeks before calving than started feeding after calving.

Effect of dietary fatty acid pattern on growth, body fat composition and antioxidant parameters in broilers.

The effects of dietary fat supplementation on performance, fatty acid (FA) composition of tissues and antioxidant defence system of broilers were studied. Male broilers were placed in 20 floor pens (60 broilers per pen). The broilers were fed by diets with added different energy sources: lard (L); sunflower oil (SFO); soybean oil (SBO); and linseed oil (LSO). The treatments did not modify significantly growth performance and feed intake of the broilers. There was no effect of dietary FA pattern on reduced glutathione level and glutathione peroxidase activity of plasma, erythrocyte and liver samples. However, higher PUFA content of the diet resulted in a significant increase in malondialdehyde level of erythrocytes and liver. The broilers fed LSO diet more effectively maintained their antioxidant status with enhanced plasma radical scavenger capacity. FA composition in tissues reflected the FA pattern of the diets, although proportion of FAs with four or more double bonds was metabolic specific. LSO diet increased the level of C18:3, C20:5 and C22:6 in tissue lipids in relation to L, SFO and SBO diets. Significantly increased plasma radical scavenging capacity in concert with the enhanced C20:5 and C22:6 proportion in liver and muscle during LSO feeding indicate metabolic changes to counteract the oxidative injury. This may be related to the compounds produced after different biochemical pathways of n-6 and n-3 FAs.

Effects of oral L-carnitine, L-lysine administration and exercise on body composition and histological and biochemical parameters in pigeons.

The purpose of this study was to examine whether L-carnitine and its precursor L-lysine could have any beneficial effect in racing pigeons, and if so, whether this effect is influenced by the extent of exercise (short-distance flight: 135 km vs. long-distance flight: 580 km). Birds were divided into seven groups of animals. Group 1: negative control, no flight, no treatment, Group 2: positive control, placebo treatment before the short-distance flight, Group 3: 200 mg/day L-carnitine treatment before the short-distance flight, Group 4: 400 mg/day L-lysine treatment before the short-distance flight, Group 5: positive control, placebo treatment before the long-distance flight, Group 6: 200 mg/day L-carnitine treatment before the long-distance flight, Group 7: 400 mg/day L-lysine treatment before the long-distance flight. L-carnitine, L-lysine and distilled water (placebo) were orally administered (tube feeding) for 7 days before flight. Just after returning home, blood samples were collected and analyzed for glucose, fructosamine, cholesterol, triglycerides and thiobarbituric acid reactive substances. Pigeons were euthanized using carbon dioxide as an inhalation agent, and the whole body was subjected to proximate analysis. The status at arrival was referred to as a basis for comparison. Sex did not affect the measured parameters. As a result of the L-carnitine and L-lysine administrations, the body fat mobilization was higher during the 580 km flight, whereas no changes were noted during the 135 km flight. The main changes in the measured blood parameters were caused by the extent of exercise. This experiment considered the extent of exercise as a factor potentially modulating L-carnitine supplementation effects. In conclusion, flight distance affected several parameters but the supplements of L-carnitine and L-lysine were not effective in the tested situations.

Investigations on the effects of Ca-soap of linseed oil on rumen fermentation in sheep and on milk composition of goats.

Six rumen-cannulated wethers were fed by a diet composed of alfalfa hay and concentrate and supplemented by 75 g Ca-soap of linseed oil (5.4% in dry matter, DM) daily. A model trial was performed to detect the effects of the Ca-soap on rumen fermentation parameters and on fibre digestion. Approximately 3 h after feeding Ca-soap, ratio of C2:C3 decreased (from 4.33 to 4.02) and the production of i- and n-butyrate and i- and n-valeriate increased by 28, 5.3, 11.76% and 6.80% respectively. Total volatile fatty acid concentration in rumen fluid did not change (126.1 vs. 126.4 mm) as a result of Ca-soap supplementation. The in vitro trial showed no detrimental influence of Ca-soap on the acid detergent fibre (ADF) degradation. Using feed samples containing Ca-soap to be incubated in tubes, ADF digestion proved to be significantly higher (p < 0.001). Approximately 14 goats (Saanen breed, 30-70 days in lactation) were used to test the effects of Ca-soap on milk composition. Their ration contained alfalfa hay, millet straw and a concentrate. In the experimental group (seven goats) the diet was supplemented with Ca-soap of linseed oil (75 g/animal/day). The milk composition was changed (slightly reduced solid content, sometimes significantly reduced milk fat contents), when Ca-soap was included in the diet of lactating goats.

Evaluation of the digestibility of nutrients in pigs by ileal cannulation technique.

A simple T-cannula was surgically inserted into the ileum of growing female Large White x Dutch Landrace swine. Chymus samples collected with the help of the cannula were analysed to determine the apparent digestibility of different dietary nutrients such as dry matter, crude protein and starch, as well as of some essential amino acids. The following three experiments were conducted: (I) of the cereals, the "Tewo" triticale variety fed alone and in 1:1 concentrate mixtures with wheat or maize was studied; (II) waxy maize hybrids and maize hybrids of normal endosperm were compared without treatment and after treatment by the Bocchi technology; (III) untreated and extruded maize supplemented either with extracted soybean or with extracted sunflower was also tested. The ileal digestibility of protein, amino acids and starch was determined and compared with values obtained by conventional (faecal) analysis. When feeding triticale alone or in combination with wheat or maize, the ileal digestibility of crude protein and amino acids increased as a result of feeding the cereal combinations (e.g. crude protein 72-79%, lysine 75-79%, threonine 63-78%, methionine 74-86%). Comparison of the two maize hybrids revealed that, with the exception of methionine, lysine and tyrosine, the amino acids of the waxy hybrid had higher ileal digestibility. Treatment of the normal hybrid by the Bocchi technology caused a significant improvement in the ileal digestibility of cystine, isoleucine, lysine, valine, and dry matter. This treatment also improved the faecal digestibility of all test nutrients but methionine. Bocchi treatment of the waxy hybrid significantly improved the ileal digestibility of isoleucine, leucine, methionine, tyrosine and valine, and the faecal digestibility of cystine, dry matter, and crude protein. No major variety- or treatment-related differences were found in the digestibility of starch. As a result of extrusion, the digestibility of nutrients of the soybean + maize mixture increased from 61.6% to 70.3% (crude protein), from 41.1% to 59.4% (threonine), from 60.1 to 72.0% (methionine), and from 70.7% to 82.7% (lysine). The same treatment of the sunflower + maize mixture increased the digestibility of crude protein from 80.6% to 84.5%, that of threonine from 78.1% to 80.6%, that of methionine from 79.7% to 84.3%, while that of lysine from 61.4% to 72.3%. The ileal digestibility of starch was 97-98% for both mixtures. As a result of extrusion, most of the faecal digestibility values showed a significant improvement for both the soybean- and the sunflower-containing mixtures. The favourable effect exerted by extrusion on the digestibility of nutrients is markedly influenced by the feed components.

The effect of animal fat and vegetable oil supplementation of feeds of different energy concentration upon the digestibility of nutrients and some blood parameters in rabbits.

The effect of mixed animal fat and sunflower oil supplementation (5%) of a feed of medium (12.02 MJ DE/kg) and low (8.54 MJ DE/kg) energy concentration upon the digestibility of nutrients and on some blood parameters was investigated. The ether-extractable content of feed and faecal samples was determined by diethyl ether extraction (after Soxhlet) and the total (true) fat level was measured by the method of Stoldt (1952), viz. petroleum ether extraction of samples pretreated with 4 N HCl. In the majority of cases the voluntary feed intake decreased after the addition of animal fat or vegetable oil. Mixed animal fat supplementation significantly (by 5 and 11 units) improved the digestibility of the ether extract if added to either of the basal diets. The digestibility of crude fibre and N-free extract increased only in the case of the basal diet of low energy concentration (by 4 and 7 units, respectively). Sunflower oil addition produced changes of the same tendency (9, 9, 28 and 5 units). The digestibility of the crude protein was practically not altered by either supplementation. The total fat content of feed and faecal samples proved to be higher than that of the ether extract, on an average by 27 and 100%, respectively. Consequently, the digestibility coefficients of the total fat are by 10 units lower than those of the ether extract. The DE concentrations, calculated by means of the digestible ether extract or the total fat content, differed significantly only between the basal diets. The addition of mixed animal fat to either of the basal diets increased the blood concentration of total lipids (by 18 and 32%, respectively), while that of sunflower oil did not cause such an alteration. Neither fat nor oil supplementation had an effect on the cholesterol level of the blood plasma. Both the animal fat and the vegetable oil surplus modified the fatty acid composition of blood lipids. It was characteristic of each treatment that the proportion of polyunsaturated fatty acids increased.