Inclusion Of Conjugated Linoleic Acid Research Articles

The Ruminal Microbiome Alterations Associated with Diet-Induced Milk Fat Depression and Milk Fat Globule Size Reduction in Dairy Goats.

The aim of this study was to evaluate the effect of conjugated linoleic acid (CLA) on milk fat globule (MFG) size and the ruminal microbiome of goats. Twenty-four mid-lactation Saanen dairy goats weighing 49 ± 4.5 kg (168 ± 27 d in milk, 1.2 ± 0.1 kg milk/d, 2-3 years old) were randomly divided into four groups-a control (CON) group, which was fed a basal diet, and three CLA supplementation groups, in which 30 g CLA (low-dose group, L-CLA), 60 g CLA (medium-dose group, M-CLA), or 90 g CLA (high-dose group, H-CLA) was added to the basal diet daily. The experiment lasted for 21 days, during which time goat milk was collected for composition and MFG size analysis. On day 21 of feeding, ruminal fluid was collected from the CON and H-CLA groups for analysis of the changes in microorganismal abundance. The results showed that CLA supplementation did not affect milk production, milk protein, or lactose content in the dairy goats (p > 0.05), but significantly reduced the milk fat content (p < 0.01) compared with the CON group. The CLA supplementation significantly decreased the D[3,2] and D[4,3] of the MFGs in a dose-dependent manner (p < 0.01). Moreover, dietary CLA inclusion increased the proportion of small-sized MFGs and decreased that of large-sized ones. The results of 16S rRNA gene sequencing showed that CLA-induced milk fat depression in dairy goats was accompanied by significant changes in the relative abundance of ruminal bacterial populations, most of which belonged to the Firmicutes and Bacteroidetes phyla. The relative abundance of Rikenellaceae_RC9_gut_group and Prevolellaceae_UCG-003 in Bacteroidetes and UCG-002, Succiniclasticum, and norank_f__norank_o__Clostridia_vadinBB60_group in Firmicutes was significantly higher in the CON group than in the H-CLA group. In contrast, the relative abundance of norank_f__UCG-011, norank_f_Eubacterium_coprostanoligenes_group, unclassified_f__Lachnospiraceae, and UCG-001 in Firmicutes and norank_f__Muribaculaceae in Bacteroidetes was significantly higher in the H-CLA group than in the CON group. Correlation analysis showed that the milk fat content was negatively correlated with the relative abundance of some bacteria, including members of Firmicutes and Bacteroidetes. Similarly, MFG size (D[3,2] and D[4,3]) was negatively correlated with several members of Firmicutes and Bacteroidetes, including Lachnospiraceae, norank_f__UCG-011, UCG-001, norank_f__Eubacterium_coprostanoligenes_group (Firmicutes), and norank_f__Muribaculaceae (Bacteroidetes), while positively correlated with the relative abundance of some members of Firmicutes and Bacteroidetes, including Mycoplasma, Succiniclasticum, norank_f__norank_o__Clostridia_vadinBB60_group, UCG-002 (Firmicutes), and Rikenellaceae_RC9_gut_group (Bacteroidetes). Overall, our data indicated that CLA treatment affected milk fat content and MFG size in dairy goats, and these effects were correlated with the relative abundance of ruminal bacterial populations. These results provide the first evidence to explain the mechanism underlying diet-induced MFG from the perspective of the ruminal microbiome in dairy goats.

Effects of dietary conjugated linoleic acid in broiler breeders and egg storage time on the fatty acid profile, lipid oxidation and internal egg quality

Context The need for the storage of fertile eggs is a reality in the poultry industry. At the same time, prolonged storage periods decrease the quality of egg components that are essential for embryo development, and can compromise hatchability and chick quality; thus, the high content of unsaturated fatty acids in embryo tissues increase the susceptibility to peroxidation. Aims The objective of this study was to evaluate the addition of cis-9, trans-11, trans-10 and cis-12 isomers of conjugated linoleic acid (CLA) to the broiler-breeder diet and the storage time on the internal egg quality, composition and lipid oxidation. Methods In total, 22 000 Cobb female broiler breeders of 58 weeks of age were fed with diets containing 0 or 0.024% CLA and fertile eggs were stored 3, 6 or 9 days prior to incubation. In total, 6912 hatching eggs were used in a completely randomised experimental design in a 2 × 3 factorial arrangement (CLA inclusion × egg storage time). At the end of each storage period, 30 eggs per dietary treatment were sampled to analyse yolk and albumen height, percentage and pH, yolk:albumen ratio, yolk diameter and index, Haugh unit (HU), yolk lipid oxidation, acidity and fatty acid profile. Key results The progression of storage negatively affected the internal quality of the eggs; however, inclusion of CLA minimised these effects up to Day 6, especially for yolk diameter, HU, height and albumen pH. The total lipid content was not affected by the dietary treatments; however, CLA inclusion resulted in a higher proportion of stearic acid and a lower concentration of linoleic acid in yolks. Conclusions The changes observed in fatty acid profile of the eggs may have favoured the reduction of lipid oxidation, as shown by the decrease in the acidity index and thiobarbituric acid-reactive substance (TBARS) values at shorter storage periods. Implications The dietary addition of CLA to broiler breeders may be used to preserve the egg internal quality during a short-term storage period.

Effect of ractopamine and conjugated linoleic acid on performance of late finishing pigs

The dietary inclusion of feed additives to improve the carcass characteristics of the final product is of great importance for the pork production chain. The aim of our study was to evaluate the effects of the association of ractopamine (RAC) and conjugated linoleic acid (CLA) on the performance traits of finishing pigs during the last 26 days prior to slaughter. In total, 810 commercial hybrid barrows were used. Animals were distributed among treatments according to a randomised block design in a 3 × 3 factorial arrangement, with three RAC levels (0, 5 or 10 ppm) and three CLA levels (0, 0.3 or 0.6%). Pigs fed the diet with 5 ppm RAC had higher average daily feed intake (ADFI) (2.83 kg; P < 0.05) when compared with those fed 10 ppm RAC and the control diet (2.75 and 2.74 kg, respectively). Lower ADFI values (P < 0.01) were observed with the diets containing CLA compared with the control diet with no CLA (2.73 and 2.75 v. 2.85 kg/day, respectively). The average daily weight gain of pigs fed 5 and 10 ppm RAC was +148 and +173 g/dayhigher (P < 0.001), respectively, than those fed the control diet. Dietary RAC levels influenced (P < 0.001) feed conversion ratio (FCR), which was reduced as RAC levels increased, with the pigs fed 10, 5 and 0 ppm RAC presenting FCR values of 2.57, 2.71 and 3.05, respectively. FCR also improved (P < 0.05) with the inclusion of 0.6% CLA relative to the control diet (2.70 v. 2.84, respectively). There was a significant interaction between CLA × RAC levels (P < 0.01) for final BW, loin eye area (LEA) (P < 0.05) and backfat thickness (BT) (P < 0.05). The treatments containing 10 ppm RAC + 0.6% or 0.3% CLA increased LEA and reduced BT. In conclusion, the level of 10 ppm inclusion of RAC increased the overall performance parameters of pigs and therefore improved production efficiency. The combined use of RAC and CLA promoted a lower feed conversion ratio as well as better quantitative carcass traits, as demonstrated by the higher LEA and lower BT. The dietary inclusion of CLA at 0.3% improved feed efficiency, however, without affecting LEA or BT yields.

Stimulatory effects of nano-selenium and conjugated linoleic acid ‎ on antioxidant activity, trace minerals, and gene expression response of growing male Moghani lambs.

Sheep keepers need suitable strategies to improve animal immunity and the quality of their products. This study was aimed to evaluate the effect of nano-selenium (nano-Se) and conjugated linoleic acid (CLA) on an antioxidant statue, trace minerals, and mRNA expression of glutathione peroxidase 1 (GPX1) and selenoprotein W1 (SEPW1) genes in the liver and peroxisome proliferator-activated receptor-gamma (PPARγ) and stearoyl COA desaturase 1 (SCD1) genes in fat- tail of male Moghani lambs. Thirty male Moghani lambs, three months old and average weight 30.00 ± 0.25 kg, were assigned to a completely randomized design in a 2×3 factorial arrangement with dietary supplementation of nano-Se (0, 1.00 and 2.00 mg kg-1 dry matter) and CLA (0.00 and 15.00 g kg-1 dry matter). The lambs were slaughtered at the end of the experiment, on day 90 of the experiment. Results showed that dietary inclusion of nano-Se significantly improved antioxidant enzymes glutathione peroxidase and superoxide dismutase in blood, however, did not show any differences in trace mineral treatments. The analysis of qPCR showed that nano-Se inclusion at the highest level (2.00 g kg-1 dry matter) enhanced gene expression of GPX1 (0.64 vs 0.34) and SEPW1 (0.72 vs 0.35) in the liver. Dietary inclusion of CLA increased the expression of PPARγ (0.63 vs 0.38) and decreased SCD1 (0.63 vs 0.33) genes in fat- tail. It could be concluded that selenium inclusion in the growing lamb’s diet could improve antioxidant status, however, no synergistic interaction was observed along with CLA on the mentioned parameters.

Effect of conjugated linoleic acid supplementation on the microbial, physical, chemical and sensory properties of yoghurt

The aim of this study was to determine the effect of synthetic conjugated linoleic acid (CLA) supplementation on the quality of yoghurt. Yoghurt was prepared by adding CLA to create yoghurt with 0%, 25%, 50% and 100% w/w of the recommended dietary allowance for CLA. CLA inclusion had no effect on the viability of the yoghurt lactic acid bacteria. Physical properties such as viscosity and pH increased with increased CLA levels. CLA inclusion had a significant effect on the fatty acid composition of the yoghurt. Yoghurts from all four treatments were found acceptable by a consumer panel.

Effects of whole linseed and rumen-protected conjugated linoleic acid enriched diets on beef quality

Instrumental assessments and sensory tests were performed to evaluate the effects of diet and postmortem ageing time (1, 7 and 21 days) on beef quality. A total of 48 Friesian calves were randomly allocated to four dietary treatments: control, whole linseed (10% linseed), conjugated linoleic acid (CLA) (2% protected CLA), and whole linseed+CLA (10% linseed and 2% protected CLA). Animals were slaughtered at 458±16.6 kg live weight and 11 months of age. Ageing was more significant than diet on most instrumental parameters. Meat from linseed enriched diets had greater drip loss (P⩽0.001) and intramuscular fat (P⩽0.01) than meat from animals fed CLA. Beef aged for 7 and 21 days had lower cooking losses (P⩽0.01) and shear force (P⩽0.001) than beef aged for 1 day. Lightness was affected only by display time. The addition of CLA in the diet increased hue and yellowness, whereas the inclusion of linseed decreased these values, as well as increased redness. Linseed in the diet decreased fat odour (P⩽0.05), but increased beef (P⩽0.01) and liver (P⩽0.05) flavours. Meat aged for 21 days was significantly more rancid (P⩽0.001), even under vacuum storage. Several organoleptic properties were improved with the inclusion of linseed in the diet, whereas they remained unaffected by the inclusion of CLA.

Effect of long term feeding with conjugated linoleic acid (CLA) in growth performance and lipid metabolism of European sea bass (Dicentrarchus labrax)

In the present study, the effects of long term feeding dietary conjugated linoleic acid (CLA) on growth, liver and perivisceral fat morphology, lipid metabolism enzymes and prostaglandin production potential were assessed. Two hundred and forty-three European sea bass (152.4±1.96g) were randomly allocated in 9 indoor 1m3 fiberglass tanks (4.1kg/m3) and assigned three diets containing graded amounts of CLA (0, 0.5 and 1%) for 20weeks. Dietary CLA did not affect growth performance or tissue proximate composition although increased the saturated fatty acid fraction in fish fed with 1% CLA in muscle. Muscle and liver fatty acid profiles were slightly altered by CLA inclusion, mainly by the increase of the CLA isomers and by the increase of 18:0 and the decrease of 16:1n-7. Liver lipogenic and lipolytic enzymes were not affected by dietary CLA. Hepatocyte area was reduced in fish fed with 1% of CLA, as well as adipocyte area in fish fed with 0.5% of CLA where adipocyte number by unit of area also increased. Head kidney prostaglandins' production potential was reduced in fish fed with 1% of CLA, having also a negative correlation with dietary CLA level of inclusion. The present results suggest that CLA can be incorporated up to 1% in 150g European sea bass for 20weeks without affecting fish performance or enzyme activities and at the time improves liver and adipose tissue morphology.

Ácido linoléico conjugado, na nutrição de suínos, sobre desempenho zootécnico, características de carcaça e rendimento de cortes

O experimento foi conduzido com o objetivo de avaliar o efeito da inclusão de ácido linoléico conjugado (CLA) em dietas de suínos dos 65kg de peso vivo até a fase de abate (100kg) sobre desempenho zootécnico, rendimento de corte e características de carcaça. Foram utilizados 200 suínos provenientes do cruzamento industrial JSR x PIC, em igual proporção de sexo. Os tratamentos foram compostos por dietas com (+CLA) e sem (-CLA) adição de CLA. O delineamento experimental utilizado foi completamente casualizado, sendo as características de carcaça avaliadas em esquema fatorial 2x2 (dieta x sexo). Os animais que consumiram CLA apresentaram melhor ganho de peso diário, redução da espessura de toucinho e maior rendimento de carne magra. A retenção de líquidos da carne não apresentou diferença em relação à dieta. Conclui-se, com base nos resultados, que é benéfica a inclusão de CLA na alimentação de suínos em terminação.

Effect of dietary conjugated linoleic acid levels on growth performance, muscle fatty acid profile, hepatic intermediary metabolism and antioxidant responses in genetically improved farmed Tilapia strain of Nile tilapia Oreochromis niloticus

An 8-week feeding trial was conducted to determine the effect of dietary conjugated linoleic acid (CLA) on growth performance, muscle fatty acid profile, hepatic intermediary metabolism and antioxidant responses in genetically improved farmed Tilapia (GIFT) strain of Oreochromis niloticus (initial body weight: 42.6 ± 0.4 g, mean ± standard deviation). Three replicated groups of GIFT strain of Nile tilapia were hand-fed to satiation, twice a day, with the diets in which CLA oil, containing mainly the bioactive cis-9, trans-11 and trans-10, cis-12 isomers, was included at 0 (control), 0.5%, 1%, 1.5%, 2% and 2.5%, respectively, at the expense of fish oil to maintain the constant lipid and energy levels. Growth performance and feed utilization showed no significant differences among the treatments (P > 0.05). The dietary inclusion of CLA modified total percentages of the main groups of fatty acids. Increasing saturated fatty acid content and reduced mono-unsaturated fatty acid contents in muscle were observed with increasing dietary CLA inclusion (P < 0.05). Total n-3 fatty acids and total polyunsaturated fatty acids tended to decline with increasing dietary CLA levels (P < 0.05), but n-6 fatty acids showed no significant differences among the treatments (P > 0.05). Dietary CLA supplementation resulted in the significant increase in the trans-10, cis-12 and cis-9, trans-11 CLA isomers in muscle (P < 0.05) and also significantly influenced several hepatic enzymatic activities, such as succinate dehydrogenase, lactate dehydrogenase, malic dehydrogenase, lipoprotein lipase and hepatic lipase activities (P < 0.05). Reduced superoxide dismutase and glutathione peroxidase activities, and the decline in malondialdehyde levels were observed in fish fed the CLA-supplemented diets (P < 0.05), indicating that dietary CLA supplementation showed a powerful antioxidant effect for this fish species. Our study was the first report involved in the effect of dietary CLA inclusion on hepatic intermediary metabolism and antioxidant responses in fish, which could be used as indicators of nutritional and physiological status of the fish species.

Effects of dietary replacement of fish oil by conjugated linoleic acid on some meat quality traits of Pacific white shrimp Litopenaeus vannamei

This experiment was conducted to evaluate the effects of fish oil replacement by conjugated linoleic acid (CLA) on body proximate analysis and thiobarbituric acid-reactive substances, fat content, shear force and fatty acid composition in musculature of Pacific white shrimp ( Litopenaeus vannamei). Graded levels of CLA (0%, 0.5%, 1% and 2%) were added to the basic diet of shrimp at the expense of fish oil. Results showed that fat content ( p = 0.036) and shear force ( p = 0.001) in shrimp musculature were enhanced with increasing dietary CLA inclusion. Fish oil replacement by CLA significantly promoted the incorporation of cis-9, trans-11 CLA ( p = 0.0001) and trans-10, cis-12 CLA ( p < 0.0001) into shrimp musculature; moreover, the polyunsaturated fatty acid was elevated ( p = 0.020) and monounsaturated fatty acid was reduced by CLA inclusion ( p = 0.024). It was concluded that replacement of fish oil by CLA could improve some meat quality traits of shrimp and 1% CLA was an appropriate amount.

Effect of dietary conjugated linoleic acid (CLA) on growth performance, body composition and hepatic intermediary metabolism in juvenile yellow catfish Pelteobagrus fulvidraco

The present study was conducted to determine the effect of dietary conjugated linoleic acid (CLA) on growth performance, body composition and hepatic intermediary metabolism in juvenile yellow catfish Pelteobagrus fulvidraco (initial body weight: 1.87 ± 0.04 g, mean ± SD). The five isonitrogenous (35% crude protein) experimental diets were formulated to contain graded CLA levels of 0 (control), 0.5, 1, 1.5 and 2%, respectively. Three replicated groups of fish were fed to satiation, twice a day, over a period of 8 weeks with CLA oil, containing mainly the bioactive cis-9, trans-11 and trans-10, and cis-12 isomers. The increase of dietary CLA levels reduced growth performance, feed conversion rate (FCR), condition factor, hepatosomatic index and viscerosomatic index of yellow catfish. Increasing dietary CLA levels significantly reduced lipid contents in the whole body and liver. The dietary inclusion of CLA modified total percentages of the main groups of fatty acids. Increasing saturated fatty acid (SFA) content and reduced mono-unsaturated fatty acid (MUFA) contents in the whole body were observed with increasing dietary CLA inclusion. A gradual reduction of 16:1 and 18:1 fatty acids was depicted in the whole body with increasing CLA levels. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) profiles showed no significant differences among the treatments. Total polyunsaturated fatty acids (PUFA) tended to increase with increasing dietary CLA levels. Dietary CLA supplementation resulted in a significant increase of the trans-10, cis-12 and cis-9, and trans-11 CLA isomers in the whole body, and also significantly influenced several hepatic enzymatic activities, such as succinate dehydrogenase (SDH), lactate dehydrogenase (LDH), malic dehydrogenase (MDH), lipoprotein lipase (LPL) and hepatic lipase (HL) activities. These indicate that despite promoting the CLA and PUFA deposition in the whole body, dietary CLA supplementation should be carefully evaluated in intensive yellow catfish farming as it reduces growth performance and feed utilization.

Meta-análise do uso de ácido linoleico conjugado na alimentação de suínos

O objetivo deste trabalho foi realizar uma meta-análise da associação do ácido linoleico conjugado (CLA) com o desempenho e a qualidade de carcaça e de carne em suínos (Sus scrofa domesticus). A base de dados utilizada contemplou 15 artigos publicados entre 1999 e 2006, e totalizou 216 dietas e 5.223 animais. A meta-análise foi realizada por meio de análises gráficas (para observar coerência biológica dos dados), de correlação (para identificar variáveis correlacionadas) e de variância-covariância. O modelo da análise de variância incluiu apenas as variáveis de carne e carcaça mais correlacionadas com o consumo de CLA pelos animais, além das codificações para os efeitos inter e intra-experimentos. A inclusão do ácido linoleico apresentou correlação negativa com a eficiência alimentar e positiva com o consumo de ração e o ganho de peso dos animais. Não houve alteração do consumo de ração, do ganho de peso e da eficiência alimentar dos suínos. O ácido linoleico conjugado aumentou em 9% o conteúdo de carne magra na carcaça, e seu consumo variou a espessura média de toucinho. O ácido linoleico conjugado aumenta o conteúdo de carne magra e reduz a espessura de toucinho na carcaça, sem influenciar o desempenho e a qualidade da carne em suínos.

Effect of conjugated linoleic acid on dietary lipids utilization, liver morphology and selected immune parameters in sea bass juveniles (Dicentrarchus labrax)

Increased energy content in fish feeds has led to an enhanced fat deposition, particularly in European sea bass, concerning fish farmers. Inclusion of conjugated linoleic acid (CLA) could reduce fat deposition as in other vertebrates. To determine if dietary CLA affects fat deposition, lipid metabolism, lipid composition and morphology of different tissues, growth and selected immune parameters, European sea bass juveniles were fed 4 graded levels of CLA (0, 0.5, 1 and 2%). Growth and feed conversion were not affected by CLA, whereas feed intake was reduced (P<0.05) by feeding 2% CLA. In these fish perivisceral fat was also reduced (P<0.05), particularly reducing (P<0.05) monounsaturated fatty acids. CLA has not affected tissue proximal composition, but reduced (P<0.05) saturated and monounsaturated fatty acids and increased (P<0.05) the n-3 and n-3 highly unsaturated fatty acids in muscle and increase (P<0.05) CLA content in muscle, liver and perivisceral fat. A progressive reduction in lipid vacuolization of hepatocytes cytoplasm and regular-shaped morphology was found in fish fed increased CLA levels, together with a progressive increase in malic enzyme activity (only significant in fish fed 1% CLA). Finally, inclusion of CLA up to 1% increased (P<0.05) plasma lysozyme activity and was positively correlated with alternative complement pathway.

Influence of dietary conjugated linoleic acid on growth, fatty acid composition and hepatic lipogenesis in large yellow croaker (Pseudosciaena crocea R.)

We examined the effects of conjugated linoleic acid (CLA) on growth, fatty acid composition and enzyme activity of fatty acid oxidation in the liver of large yellow croaker. We divided 1600 fish (average initial weight 150 g) into 4 groups and reared them in 8 cages. Four dietary treatments were formulated to contain 0%, 1%, 2% and 4% (w/w) CLA, respectively. The fish were fed for 10 weeks ad libitum twice daily. We found that the dietary CLA had no effect on growth, biometric parameters and whole body proximate (P>0.05), but showed some significant effects on the fatty acid composition in both muscle and the liver. The activities of lipogenic enzymes were slightly depressed in fish fed with increasing levels of CLA when compared with control (P>0.05). Dietary CLA supplementation had no effects on liver lipid content, but significantly increased the contents of saturated fatty acids (SFA) and polyunsaturated fatty acids (PUFA) (P<0.05) and decreased monounsaturated fatty acid (MUFA) content in both muscle and the liver. Dietary CLA inclusion resulted in significant increases of the biologically active cis-9, trans-11 and trans-10, cis-12 isomers in both tissues (P<0.05). The total accumulation of CLA was higher in the liver (3.83%, w/w) than in muscle (3.77%, w/w) when fed with 4% (w/w) CLA. This study demonstrates that large yellow croakers are capable of absorbing and depositing CLA and long-chain n-3 PUFA in the liver and muscle, showing that this species fed with CLA could be an important human food source for these healthful fatty acids.

Changes in the Fatty Acid Profile of the Subcutaneous Fat of Swine throughout Fattening As Affected by Dietary Conjugated Linoleic Acid and Monounsaturated Fatty Acids

The fatty acid profile of the subcutaneous fat of pigs and its evolution throughout fattening as affected by dietary conjugated linoleic acid (CLA), monounsaturated fatty acids (MUFA), and their interaction (CLAxMUFA) were studied. Three levels (0, 1, and 2%) of an enriched CLA oil (28% cis-9, trans-11 and 28% trans-10, cis-12 CLA) were combined with two levels of MUFA (low, 19% average; and high, 39% average) for pig feeding (288 gilts). Subcutaneous shot-biopsies were taken from 48 animals at the beginning of the trial (S1, 70 kg), 14 days later (S2, 80 kg), and at slaughter (S3, 107 kg). Inclusion of CLA in the diet caused an increase during fattening in cis-9, trans-11 CLA, trans-10, cis-12 CLA, and saturated fatty acids (SFA) contents of pig backfat and a decrease in MUFA and polyunsaturated fatty acids (PUFA). MUFA supplementation also led to a MUFA enrichment of backfat. The interaction CLAxMUFA affected the SFA content. The rates of accumulation of CLA isomers, SFA, and MUFA throughout the trial did not follow a linear behavior, such rates being higher from S1 to S2 than from S2 to S3. These rates were also influenced by dietary CLA and MUFA levels. The increase in the ratio of saturated to unsaturated fatty acids of backfat caused by dietary CLA might be balanced by supplementation of pig diets with MUFA.

DIGESTIBILITY OF NUTRIENTS WITH THE INCLUSION OF CONJUGATED LINOLEIC ACID IN THE DIET OF DOGS

The inclusion of the conjugated linoleic acid (CLA) in food for dogs has been displaying greatpotential, taking into account several benefits in regard to the use of this product. To determine the effect of CLAon the digestibility of the dry matter, nutrients and energy in dogs, two experiments were performed using dogs ofBeagle type, in the age of seven and 15 months, respectively. The experimental diets were isonutritive, justdiffering by the inclusion of CLA, watching for the addition to the control-diet, of an amount of lipids in the form ofchicken fat equivalent to the amount of CLAadded (0.3%), so that the diets were isoenergetic. The coefficients ofapparent digestibility of the dry matter, crude protein, ethereal extract and nitrogen-free extract were not affectedby the inclusion of conjugated linoleic acid, showing that the addition of the product did not interfere with theprocess of digestion of nutrients. In both digestibility experiments, higher values of metabolizable energy wereobserved for the diets with inclusion of CLA(P &lt; 0.01) when compared with the control-diet.

Instrumental measurement of the texture of hard-boiled egg yolks enriched with different levels of conjugated linoleic acid

There is increased interest in enhancing the conjugated linoleic acid (CLA) content of food products because of its potential health benefits. Inclusion of CLA in the diets of laying hens has led to the incorporation of CLA into eggs, changes in yolk fatty acid (FA) composition and non-acceptable greater firmness of hard-boiled egg yolks. This study was designed to develop instrumental tests to determine the texture characteristics of hard-boiled egg yolks obtained from hens fed diets supplemented with different levels of CLA and other fat sources. Two compression tests have established relationship between some FA levels added to diets and the firmness of boiled egg yolks. There were significant differences in the compression parameters among egg yolks from laying hens fed diets supplemented with 3 and 5 g/kg of CLA (without other fats in diet) and commercial egg yolks. Supplementations with 30 and 35 g/kg of high oleic sunflower oil (HOSO) in diets which included 3 g/kg of CLA, decreased compression parameters to levels similar to commercial eggs.

The influence of dietary conjugated linoleic acid on blood serum and colostrum immunoglobulin G concentration in female goats before and after parturition

The effects on blood serum and colostrum immunoglobulin G (IgG) levels from including conjugated linoleic acid (CLA) in the diet were evaluated in goats. In experiment 1, 20 goats were allotted into two groups; the CLA group received 20 g/kg of dry matter of CLA 60 and the control group received 0 g/kg of CLA 60, from the third month of gestation until partum. Blood samples were taken every 2 weeks from 1 day before CLA inclusion to partum. From partum until 96 hours, blood and colostrum samples were taken every 24 h. Before partum, IgG serum blood levels were 15.6 and 9.4 mg/ml (CLA and control, respectively); the time effect was statistically significant. After partum (96 h), the effect of CLA dietary inclusion was statistically significant.

Conjugated linoleic acid pork research

The driving force behind most conjugated linoleic acid (CLA) research in swine has been related to potential improvements in animal production. Early work that used rodent models indicated that feeding CLA could potentially reduce body fat, increase lean content, increase growth rate, and improve feed conversion efficiency. Producer-backed funding organizations were, therefore, receptive to proposals to extend this research to pigs, and many studies have been completed worldwide. In general, improvements in body composition were found, but evidence indicating that CLA improves growth rate or feed conversion was limited. Inclusion of CLA into pig diets was, however, shown to increase muscle marbling fat and fat hardness, and both of these characteristics have the potential to increase carcass value. Currently, Badische Anilin- & Soda-Fabrik AG (BASF) has the international marketing license to include synthetic CLA in animal feeds, but to date this practice is not approved in Canada or the United States. If and when approval is granted, the next step in realizing CLA's economic potential would be to seek approval for claiming CLA enrichment in pork and pork products. Given the ability of swine to accumulate relatively high amounts of CLA in their tissues, pork and pork products could become an important vehicle for delivery of physiologically significant amounts of CLA to consumers.

Effects of conjugated linoleic acid addition on its deposition in eggs of laying hens, fed with no other fat source

An experiment was conducted to investigate the retention of conjugated linoleic acid (CLA) in eggs of laying hens by replacing 1, 2 or 3% of a control diet with no fat added with a commercial source of CLA. Sixty four 40-weeksold Warren laying hens were used to determine the effect of treatments on productive traits, yolk fatty acids composition and egg quality. The data were collected over a 56-days experimental period, following a 21-days adaptation period. Type of diet did not affect feed intake, laying rate, egg or yolk weight, although weight gain of hens decreased linearly (P &lt; 0.001) with level of CLA inclusion. Concentration of CLA in yolk fat increased with dietary CLA addition, reaching a value of 10.5% for the 3%-CLA diet. Efficiency of retention of CLA decreased linearly (P&lt; 0.001) with level of CLA inclusion, from 24.1 to 18.6% between the extreme diets. An increase of dietary CLA led to an increase of saturated and a decrease of monounsaturated and n-3 polyunsaturated fatty acids (P &lt; 0.001). These changes were greater at lower levels of CLA inclusion. Sensory evaluation showed that texture of eggs produced at any CLA level was not acceptable for consumption.