Conjugated linoleic acid in combination with supplemental dietary fat alters pork fat quality

Use of Microorganisms as Nutritional and Functional Feedstuffs for Nursery Pigs and Broilers

The objectives of this review paper are to introduce the structures and composition of various microorganisms, to show some applications of single cells as alternative protein supplements or energy feeds in swine and poultry diets, and to discuss the functional effects of microorganisms as feed additives on the growth performance and intestinal health of nursery pigs and broilers. Microorganisms, including bacteria, yeasts, and microalgae, have been commonly supplemented in animal diets because they are cost-effective, stable, and have quantitative production that provides nutritional and functional benefits to pigs and broilers. Microorganisms could be alternative antibiotics to enhance intestinal health due to bioactive components from cell wall components, which interact with receptors on epithelial and immune cells. In addition, bioactive components could be digested by intestinal microbiota to produce short-chain fatty acids and enhance energy utilization. Otherwise, microorganisms such as single-cell protein (SCP) and single-cell oils (SCOs) are sustainable and economic choices to replace conventional protein supplements and energy feeds. Supplementing microorganisms as feedstuffs and feed additives improved the average daily gain by 1.83%, the daily feed intake by 0.24%, and the feed efficiency by 1.46% in pigs and broilers. Based on the properties of each microorganism, traditional protein supplements, energy feeds, and functional feed additives could be replaced by microorganisms, which have shown benefits to animal's growth and health. Therefore, specific microorganisms could be promising alternatives as nutritional and functional feedstuffs in animal diets.

Create Fat Substitute From Soybean Protein Isolate/Konjac Glucomannan: The Impact of the Protein and Polysaccharide Concentrations Formulations

In this study, soybean protein isolate (SPI) and coconut oil were emulsified and konjac flour was added to prepare the protein/polysaccharide composite emulsion gel. The SPI/polysaccharide compound fat substitute was obtained by vacuuming. The effects of protein and konjac flour addition on the gel system of the mixed emulsion were explored. Sensory evaluation experiments showed that the overall acceptability of fat substitutes added with 1% SPI was higher. With the increase of protein and konjac content, the juiciness of the samples decreased gradually. The increase of konjac content reduced the brightness of compound fat substitutes, and the yellowness of compound fat substitute increases significantly with the increase of protein content. The rheological results showed that the G′ and loss modulus (G″) increased with the increase of protein and konjac content, forming a rigid elastic gel matrix, which provided a basis for the preparation of fat substitutes. Texture profile analysis (TPA) results showed that the springiness of all samples was similar to the natural fat after 20 min of heating. With the increase of protein and konjac content, the hardness of the samples increased gradually. The results of oral tribology showed that the friction coefficients of all samples were very small. The friction behavior of the samples with SPI content of 1% was similar to that of natural fat, which could better simulate the swallowing feeling and lubricity of natural fat. To sum up, the appearance of solid fat substitutes prepared with SPI and konjac flour is similar to pork fat. They show ideal functional characteristics in mechanical properties and oral tribology. Among them, the fat substitute with the protein content of 1% and konjac content of 4% is the most popular among consumers.

Effects of Yarrowia lipolytica supplementation on growth performance, intestinal health and apparent ileal digestibility of diets fed to nursery pigs

Objective

The objective was to evaluate the efficacy of increasing supplementation of Yarrowia lipolytica (YL) up to 3.0% replacing 1.6% poultry fat and 0.9% blood plasma for growth performance, intestinal health and nutrient digestibility of diets fed to nursery pigs.

Methods

Twenty-four pigs weaned at 24 d of age (initial body weight at 7.2±0.6 kg) were allotted to three dietary treatments (n = 8) based on the randomized complete block. The diets with supplementation of YL (0.0%, 1.5%, and 3.0%, replacing poultry fat and blood plasma up to 1.6% and 0.9%, respectively) were fed for 21 d. Feed intake and body weight were recorded at d 0, 10, and 21. Fecal score was recorded at every odd day from d 3 to 19. Pigs were euthanized on d 21 to collect proximal and distal jejunal mucosa to measure intestinal health markers including tumor necrosis factor-alpha, interleukin-8, immunoglobulin A and immunoglobulin G. Ileal digesta was collected for apparent ileal digestibility (AID) of nutrients in diets. Data were analyzed using Proc Mixed of SAS.

Results

Supplementation of YL (1.5% and 3.0%) replacing poultry fat and blood plasma did not affect growth performance, fecal score and intestinal health. Supplementation of YL at 1.5% did not affect nutrient digestibility, whereas supplementation of YL at 3.0% reduced AID of dry matter (40.2% to 55.0%), gross energy (44.0% to 57.5%), crude protein (52.1% to 66.1%), and ether extract (50.8% to 66.9%) compared to diets without supplementation.

Conclusion

Yarrowia lipolytica can be supplemented at 1.5% in nursery diets, replacing 0.8% poultry fat and 0.45% blood plasma without affecting growth performance, intestinal health and nutrient digestibility. Supplementation of YL at 3.0% replacing 1.6% poultry fat and 0.9% blood plasma did not affect growth performance and intestinal health, whereas nutrient digestibility was reduced.

Evaluation of feeding periods of dietary conjugated linoleic acid supplementation on growth performance, nutrient digestibility, blood profiles, and meat quality in finishing pigs

This study was conducted to evaluate feeding periods of dietary conjugated linoleic acid (CLA) supplementation on growth performance, nutrient digestibility, blood profiles, and meat quality in finishing pigs. A total of 150 finishing pigs [(Yorkshire × Landrace) × Duroc] with an average body weight (BW) of 83.13 ± 1.91 kg were randomly allocated into one of three treatments (10 pens per treatment, five pigs per pen) based on their BW. Dietary treatments consisted of supplementing the basal diet with 1.0% CLA during 2, 3, and 4 wk prior to finishing. Pigs fed CLA diets 2 wk before finishing had a higher overall average daily gain (ADG) and gain-to-feed ratio (G/F) than those fed CLA diets 4 wk before finishing (P < 0.05). In the whole experiment, pigs fed CLA diets 2 wk before finishing had a higher serum low-density lipoprotein (LDL) than those fed CLA diets 3 and 4 wk before finishing. However, pigs that received CLA diets 4 wk before finishing had higher triglyceride levels (P < 0.05). Feeding 1% CLA diets 4 wk before finishing improved meat color and firmness. Taken together, feeding 1% CLA diet 4 wk before finishing increased ADG, G/F, and serum LDL, but reduced serum triglyceride.

Current feeding strategies to improve pork intramuscular fat content and its nutritional quality

Pork, one of the most consumed meats worldwide, has been facing major challenges regarding its low sensory quality and unhealthy image of fat. This chapter addresses current feeding strategies to ameliorate pork sensory attributes and nutritional quality by increasing intramuscular fat deposition and improving fatty acid composition, respectively. Dietary protein reduction, alone or combined with some components, contributes to satisfy consumer requirements and enhances the competitiveness of the meat industry with higher pork quality and lower production costs. In addition, feeding sources of n-3 polyunsaturated fatty acids to pigs, mainly from marine origin (rich in eicosapentaenoic and docosahexaenoic acids), increases their content in pork, thus improving the health value of its fatty acid profile. In the near future, the inclusion of microalgae and seaweeds in feed represents a promising approach for the maintenance and development of the livestock sector, as an environmental friendly alternative to balance food and feed industries.

TRIENNIAL GROWTH AND DEVELOPMENT SYMPOSIUM: Genetics and breeding for intramuscular fat and oleic acid content in pigs

The intramuscular fat (IMF) and oleic acid (OL) content have been favorably related to pork quality and human health. This influences the purchasing behavior of consumers and, therefore, also shifts the attention of breeding companies toward whether these traits are included into the breeding goal of the lines producing for high-valued markets. Because IMF and OL are unfavorably associated with lean content, a key economic trait, the real challenge for the industry is not simply to increase IMF and OL, but rather to come up with the right trade-off between them and lean content. In this paper we review the efforts performed to genetically improve IMF and OL, with particular reference to the research we conducted in a Duroc line aimed at producing high quality fresh and dry-cured pork products. Based on this research, we conclude that there are selection strategies that lead to response scenarios where IMF, OL, and lean content can be simultaneously improved. Such scenarios involve regular recording of IMF and OL, so that developing a cost-efficient phenotyping system for these traits is paramount. With the economic benefits of genomic selection needing further assessment in pigs, selection on a combination of pedigree-connected phenotypes and genotypes from a panel of selected genetic markers is presented as a suitable alternative. Evidence is provided supporting that at least a polymorphism in the leptin receptor and another in the stearoyl-CoA desaturase genes should be in that panel. Selection for IMF and OL results in an opportunity cost on lean growth. The extent to which it is affordable relies on the consumers' willingness to pay for premium products and on the cost to benefit ratio of alternative management strategies, such as specific dietary manipulations. How the genotype can influence the effect of the diet on IMF and OL remains a topic for further research.

Strategies for Producing and Incorporating Conjugated Linoleic Acid–Rich Oils in Foods

Conjugated linoleic acid (CLA) is in ruminant-derived foods and is known to combat obesity-related diseases. However, CLA levels in a healthy diet are too low to produce a clinical effect. Therefore, CLA has been produced by linoleic isomerization through fermentation and chemical catalysis. Many of these techniques are not practical for food production, but a recent development has enabled production of CLA-rich triglyceride vegetable oils from high linoleic acid oils by a minor modification of conventional food-oil processing techniques. These oils were used to produce common lipid-based food, such as margarine, shortenings, and salad dressings, whose quality was enhanced by the presence of CLA-rich oil and provided a significant CLA source. Meat and egg CLA content and subsequent food quality can also be increased by addition of dietary CLA. However, consumer awareness of CLA benefits needs to increase prior to commercial-scale production of CLA-rich oil.

Review: Pork belly quality, bacon properties and recent consumer trends

Soladoye, P. O., Shand, P. J., Aalhus, J. L., Gariépy, C. and Juárez, M. 2015. Review: Pork belly quality, bacon properties and recent consumer trends. Can. J. Anim. Sci. 95: 325–340. Several factors can affect pork belly quality and, subsequently, bacon quality. Going by the recent trends in the bacon market and bearing in mind the more choosy nature of the consuming populace, it is imperative to consider the factors that can affect or improve bacon quality, thereby sustaining the current market surge. In as much as both genetic and environmental factors have been identified as largely affecting muscle food quality, nutritional interventions also seem to be a very viable tool to improve the quality of meat and its products. Processing and storage methods can also affect bacon quality, including microbial quality, physicochemical attributes and palatability. Both objective and subjective measures have been explored in assessing belly quality, most of which use belly softness and fatty acid profile as yardsticks, whereas bacon quality has been widely assessed only subjectively in terms of fat quality and slice integrity. Although consumers’ and producers’ quality perceptions seem to be in conflict, it is the responsibility of all stakeholders in the bacon industries to come together in ensuring a balanced approach to satisfy both parties along the production chain.

Effects of conjugated linoleic acid or betaine on the growth performance and fatty acid composition in backfat and belly fat of finishing pigs fed dried distillers grains with solubles

The objectives of this study were to determine the effects of conjugated linoleic acid (CLA) or betaine on the growth performance, carcass characteristics and fatty acid composition in backfat and belly fat of pigs fed distillers dried grains with solubles (DDGS). Thirty-two (60±2 kg) crossbred barrows (Duroc×Landrace×Yorkshine) were assigned to one of four diets randomly: (1) the control diet containing no corn DDGS (control group); (2) the diet containing 30% corn DDGS (DDGS-fed group); (3) the diet containing 30% corn DDGS and 10 g/kg CLA (CLA-fed group); (4) the diet containing 30% corn DDGS and 1 g/kg BET (BET-fed group). The pigs fed DDGS showed that the percentages of C18:2, polyunsaturated fatty acid (PUFA) and iodine value (IV) increased, while C18:1, saturated fatty acid (SFA) and monounsaturated fatty acid (MUFA) decreased. Pigs fed the DDGS+CLA or DDGS+betaine diets showed the increased percentage of SFA, and the decreased percentage of C18:2, PUFA and IV. In conclusion, results confirmed that the diets containing 30% DDGS had no detrimental effects on growth performance, but increased the percentage of PUFA and IV and decreased the percentage of SFA and MUFA in the backfat and belly fat. However, supplementation with CLA or BET can part reverse these effects on carcass fat in finishing pigs.

Effect of dietary conjugated linoleic acid supplementation on the technological quality of backfat of pigs

Pigs were fed diets containing 0, 0.25, 0.5 and 1% conjugated linoleic acid (CLA). Compared to controls, backfat from CLA fed pigs was firmer and extracted lipid contained increasing amounts of CLA, but a ±11% overall decrease in unsaturated fatty acids and a ±5% overall increase in each of C16:0 and C18:0 saturated fatty acids were noted. This resulted in a change in the melting properties of fat. The onset setting temperature increased from ±14°C to ±18°C for lipid of backfat of pigs from the 0.25 and 0.5% CLA supplementation groups, and to ±26°C for lipid from the 1% CLA supplementation group. The final melting temperatures increased from ±37°C to ±43°C and ±45°C, respectively. The presence of β'-crystals of C18:0-C16:0-C18:1c9 triacylglycerides in fat from CLA fed pigs and β-crystals in fat from 1% CLA fed pigs was observed. Fatty acid and melting point results explained the improvement in the technological quality of backfat as a result of dietary CLA supplementation.

Effect of a high dose of CLA in finishing pig diets on fat deposition and fatty acid composition in intramuscular fat and other fat depots

Sixteen gilts were fed a control (4% of sunflower oil) or an experimental diet (4% conjugated linoleic acid (CLA) oil). CLA had no effect on intramuscular fat (IMF) content neither in longissimus thoracis (LT) nor in semimembranosus (SM) muscles but increased liver weight, reduced perirenal fat and tended to reduce backfat between the last 3th-4th lumbar vertebrae. Despite the fact that 9c,11t and 10t,12c CLA isomers were included in the same proportion in the diet, the 9c,11t and 9c,11c were the isomers more deposited in all tissues. Addition of CLA in the diet affected fatty acid composition in a tissue specific manner, increasing percentages of SFA in all tissues, reducing percentages of MUFA in LT and LT subcutaneous fat, and of PUFA in LT subcutaneous fat, liver and SM. The FA modification by dietary CLA in LT IMF was reflected in the different lipid fractions, SFA and MUFA mainly in the neutral lipid fraction, and PUFA in the polar fraction.

The effect of corn distiller's dried grains with solubles, ractopamine, and conjugated linoleic acid on the carcass performance, meat quality, and shelf-life characteristics of fresh pork following three different storage methods

The objective of this study was to evaluate dietary corn distiller's dried grains with solubles (DDGS), ractopamine hydrochloride (RAC), and conjugated linoleic acid (CLA) on growth performance, carcass and fat quality, and shelf-life of fresh pork from finishing pigs. Barrows (n=72) were fed one of eight treatments consisting of two diet sources (corn-soy and corn-soy+20% DDGS), two levels of RAC (0 and 7.4ppm), and two levels of CLA (0 and 0.6%) for 28days. Loins were portioned (n=3) into one of three storage conditions (fresh, cold, frozen); each followed with seven days of retail display. Feeding RAC improved ADG and G:F (P<0.05), whereas DDGS decreased belly fat firmness (P<0.05). Dietary DDGS increased total polyunsaturated fatty acids in jowl and belly samples and increased Iodine Value (IV) (P<0.05), but addition of CLA decreased IV. Dietary DDGS, RAC, or CLA had minimal impact on pork quality following varied storage methods.

Effect of dietary conjugated linoleic acid on marbling and intramuscular adipocytes in pork

Dietary CLA has been reported to decrease backfat and increase marbling in pigs. Our objective was to determine whether the increase in marbling involved changes in intramuscular adipocyte number or size or both. Twenty barrows (53 kg) were penned in pairs and pens were randomly assigned to receive diets containing either 1% soybean oil (SBO) or CLA (60% CLA isomers) for 6 wk. Body weight and feed intake were determined weekly. At slaughter, loin samples were obtained and flash frozen for RNA extraction and real-time reverse-transcription PCR analysis of gene expression. After a 24-h chill, loin eye area and backfat depth were measured and subjective marbling and color scores were assigned. Loin, backfat, and belly fat samples were obtained for fatty acid analysis by gas chromatography. Loin samples were also frozen in ice-cold isopentane for histological analysis of intramuscular adipocytes. Dietary CLA did not affect BW or feed intake at any point (P > 0.10), nor did treatment groups differ in HCW (P = 0.417) or loin color (P = 0.500). The CLA-fed pigs did have less (P = 0.018) backfat and smaller (P = 0.047) loin eye area than SBO-fed pigs and had a trend for an increase (P = 0.069) in marbling score. Relative gene expression for markers of preadipocytes (preadipocyte factor 1; Pref-1), differentiating adipocytes (PPARγ), and mature adipocytes [fatty acid binding protein 4 (FABP4) and perilipin (PLIN)] were determined and normalized to the expression of acidic ribosomal phosphoprotein. No significant differences were detected, but the expression of PPARγ (P = 0.265), PLIN (P = 0.265), and FABP4 (P = 0.148) was numerically greater in CLA-fed pigs than in SBO-fed pigs. Loin samples were stained with Oil Red O to identify intramuscular adipocytes. The average cell area was increased (P = 0.030) in CLA-fed pigs. The cis-9,trans-11 and trans-10,cis-12 CLA isomers were incorporated (P = 0.006) into backfat and belly fat, but only trans-10,cis-12 CLA was increased in the loin (P = 0.004) of CLA-fed pigs. The proportion of SFA was increased (P = 0.006) by CLA in all tissues. These results indicate that the increase in marbling in pigs fed CLA may be related to increased intramuscular adipocyte size, and the combination of increased marbling and degree of saturation could improve the eating quality of CLA-fed pork.

Promotion of intramuscular fat accumulation in porcine muscle by nutritional regulation

Recently, pork with marbling has received attention as good quality pork and scientists are required to develop methods to produce pork with reasonable amounts of intramuscular fat (IMF). The aim of this review is to describe studies relevant to promotion of IMF accumulation in porcine muscle by nutritional regulation. The main focus is on effect of dietary lysine levels. First, we found dietary low lysine up-regulated glucose transporter protein 4 messenger (m)RNA expression in Longissimus dorsi (L. dorsi) and Rhomboideus muscles. In addition, the proportion of oxidative fiber of both muscles was also enhanced by dietary low lysine. Because it has been observed that higher oxidative capacity is associated with higher IMF content, we hypothesized that dietary low lysine would promote IMF accumulation. Further, higher mRNA abundance of peroxisome proliferator-activated receptor γ, a master regulator of adipogenesis, in both muscles induced by dietary low lysine, supported this hypothesis. Indeed, IMF content of L. dorsi muscle of finishing pigs given a low lysine diet for 2 months until reaching the market weight was twice that of pigs given a control diet. Possible underlying mechanisms of IMF accumulation in porcine muscle and future perspectives are also discussed in this review.

Relationship between proteome changes of Longissimus muscle and intramuscular fat content in finishing pigs fed conjugated linoleic acid

The present experiment was conducted to determine proteome changes in Longissimus muscle of finishing pigs fed conjugated linoleic acid (CLA), in association with alteration of intramuscular fat content. Previously, seventy-two Duroc × Landrace × Large White gilts (approximately 60 kg) had been fed maize–soyabean meal-based diets with 0, 12·5 and 25 g CLA/kg diet. The CLA contained 369·1 mg/g cis-9, trans-11 CLA, 374·6 mg/g trans-10, cis-12 CLA and 53·7 mg/g other isomers. Six pigs per treatment were slaughtered when they reached a body weight of approximately 100 kg. Data published from a previous experiment demonstrated that supplementation with 12·5 or 25 g CLA/kg diet increased intramuscular fat content (P < 0·05). The present study investigated the proteome changes in Longissimus muscle of control and pigs supplemented with 25 g CLA/kg diet. CLA significantly influenced the abundance of proteins related to energy metabolism, fatty acid oxidation and synthesis, amino acid metabolism, defence, transport and other miscellaneous processes (P < 0·05). The increase in intramuscular fat content was positively correlated with the increased abundance of carbonic anhydrase 3 and aspartate aminotransferase (P < 0·05). We suggest that the proteome changes in Longissimus muscle contributed to greater intramuscular lipid content in CLA-supplemented pigs.

Improving functional value of meat products

In recent years, much attention has been paid to develop meat and meat products with physiological functions to promote health conditions and prevent the risk of diseases. This review focuses on strategies to improve the functional value of meat and meat products. Value improvement can be realized by adding functional compounds including conjugated linoneleic acid, vitamin E, n3 fatty acids and selenium in animal diets to improve animal production, carcass composition and fresh meat quality. In addition, functional ingredients such as vegetable proteins, dietary fibers, herbs and spices, and lactic acid bacteria can be directly incorporated into meat products during processing to improve their functional value for consumers. Functional compounds, especially peptides, can also be generated from meat and meat products during processing such as fermentation, curing and aging, and enzymatic hydrolysis. This review further discusses the current status, consumer acceptance, and market for functional foods from the global viewpoints. Future prospects for functional meat and meat products are also discussed.

Factors influencing the differentiation of bovine preadipocytes in vitro

Our objectives were to isolate bovine stromal-vascular cells using explants and to determine media components that promote differentiation into mature adipocytes for studies of lipogenic enzyme regulation. Stromal-vascular cells were grown from explants and treated with differentiation media for 8 d after reaching confluence. Differentiation was assessed by measuring radiolabeled acetate incorporation into lipids, glycerol-3-phosphate dehydrogenase activity, and the mRNA expression of fatty acid binding protein-4, PPAR-gamma, and acetyl-CoA carboxylase-alpha (ACCalpha). After 8 d of differentiation, medium containing 10 microg/mL of insulin, 0.25 microM dexamethasone, 0.5 mM isobutylmethylxanthine, 1 mM octanoate, and 2% Intralipid (Fisher Scientific, Suwanee, GA) produced greater acetate incorporation (P < 0.001) and glycerol-3-phosphate dehydrogenase activity (P < 0.001) compared with other media tested. This differentiation medium also increased mRNA expression of fatty acid binding protein-4, PPARgamma, and ACCalpha by 180-, 7-, and 3-fold, respectively, compared with undifferentiated control cells (P < 0.05). To further improve the differentiation protocol, the effects of Intralipid, rosiglitazone, and troglitazone were examined. Removal of 2% Intralipid did not improve any differentiation measures. Addition of rosiglitazone (1 microM), a PPAR-gamma agonist, increased acetate incorporation and ACCalpha mRNA (P < 0.01). Addition of troglitazone (5 microM), another PPAR-gamma agonist, increased acetate incorporation to a similar extent as rosiglitazone and produced the greatest expression of ACCalpha mRNA (P < 0.01), but was not superior to medium that included rosiglitazone for any other differentiation measures. Cell-seeding density influences the cell divisions required to reach confluence, and increased plating density (2 x 10(4) cells/cm(2) vs. 6.7 x 10(3) cells/cm(2)) increased acetate incorporation by 100% (P < 0.001). Differentiating stromal-vascular cells in the presence of trans-10, cis-12 CLA inhibited differentiation of stromal-vascular cells into mature adipocytes, reducing radiolabeled acetate incorporation into lipids (P < 0.001), stearoyl-CoA desaturase-1 mRNA (P < 0.05) and protein abundance (P < 0.05), and ACCalpha protein abundance (P < 0.05). We have developed a method to differentiate primary bovine adipocytes, which will allow us to study the regulation of lipogenic enzymes by nutrient and endocrine factors.

Interactive effects of dietary fat source and slaughter weight in growing-finishing swine: I. Growth performance and longissimus muscle fatty acid composition

Crossbred pigs (n=288) were used to test the interactive effects of dietary fat source and slaughter weight on live performance, carcass traits, and fatty acid composition of the LM. Pigs were blocked by initial BW, and, within each of 9 blocks, pens (8 pigs/pen) were randomly assigned to either control corn-soybean meal grower and finisher diets devoid of added fat (Ctrl) or diets formulated with 5% beef tallow (BT), poultry fat (PF), or soybean oil (SBO). Immediately after treatment allotment, as well as at mean block BW of 45.5, 68.1, 90.9, and 113.6 kg, 1 pig was randomly selected from each pen, slaughtered, and allowed to chill for 48 h at 1 degrees C. Backfat was measured on the right sides, and a sample of the LM was removed for fatty acid composition analysis. Regardless of source, inclusion of fat in swine diets did not (P >or= 0.349) affect ADG, ADFI, or G:F. Furthermore, carcasses from pigs fed diets formulated with 5% fat had greater (P=0.013) average backfat depths than those from pigs fed the Ctrl diet. Body weight, carcass weight, and backfat depths increased (P<0.001) as slaughter weight increased from 28.1 to 113.6 kg. The proportion of SFA in the LM increased (P<0.001) with increasing slaughter weight from 28.1 to 68.1 kg, but SFA percentages were similar between 68.1 and 113.6 kg, and pigs fed the Ctrl diet had greater (P=0.032) proportions of SFA than pigs fed the SBO and PF diets. Moreover, the proportion of all MUFA increased (P<0.001) by 9.4 percentage units from 28.1 to 113.6 kg; however, only pigs fed the SBO diet had reduced (P=0.004) MUFA percentages than those fed the Ctrl, BT, and PF diets. Even though the proportion of PUFA in the LM decreased with increasing slaughter weight, pigs fed SBO had greater PUFA percentages, a greater PUFA-to-SFA ratio, and greater iodine values than pigs fed all other dietary treatments when slaughtered at BW of 45.5 kg or greater (fat source x slaughter weight, P < 0.001). Results of this study indicate that fat source had little to no impact on live pig performance, but feeding a polyunsaturated fat source altered the fatty acid profile of the LM within the first 17.4 kg of BW gain; more specifically, including 5% SBO in swine diets could lead to economical ramifications associated with soft pork or fat.

Performance and tissue fatty acid profiles in veal calves fed diets supplemented with conjugated linoleic acids

Three groups of six calves each were fed a milk replacer at 0.8 kg and a starter concentrate ad libitum. Calves of the control group received the basal diet supplemented with rapeseed oil at 10 g per kg of feed solids. Calves of treatment groups were fed diets supplemented with a synthetically produced oil containing 62.3% methyl esters of CLA. The CLA-oil was added to milk at expense of rapeseed oil and fed at 5 and 10 g x kg(-1) feed solids for 63 days. Calves were slaughtered at 115 days of age. There was no significant effect of CLA on growth, intake of starter, feed conversion, chemical composition of meat and its oxidative stability. Dietary supplementation with CLA at 10 g x kg(-1) significantly increased CLA content in m. longissimus dorsi (MLD) from 5.6 to 19.3 mg x 100 g(-1), in liver from 13.1 to 68.8 mg x 100 g(-1), and in perirenal fat from 0.37 to 3.17 g x 100 g(-1). Dietary CLA decreased the ratio of cis-9, trans-11 and trans-10, cis-12 isomers of CLA in tissues, concentration of monounsaturated fatty acids in the MLD and fat, as well as the concentration of fatty acids with 20 and 22 carbon atoms. It can be concluded that in veal calves unprotected CLA apparently escaped ruminal hydrogenation, but was preferentially incorporated into depot fat.

Enrichment of intestinal mucosal phospholipids with arachidonic and eicosapentaenoic acids fed to suckling piglets is dose and time dependent

Infant formula companies began fortifying formulas with long-chain PUFA in 2002, including arachidonic acid (ARA) at approximately 0.5% of total fatty acids. The primary objective of this study was to determine the time-specific effects of feeding formula enriched with supra-physiologic ARA on fatty acid composition of intestinal mucosal phospholipids. One-day-old pigs (n = 96) were fed a milk-based formula for 4, 8, or 16 d. Diets contained either no PUFA (0% ARA, negative control), 0.5% ARA, 2.5% ARA, 5% ARA, or 5% eicosapentaenoic acid (EPA) of total fatty acids (wt:wt). Growth (299 +/- 21 g/d) and clinical hematology were unaffected by treatment (P > 0.6). Although minimal on d 4, concentrations of ARA in jejunal mucosa were enriched 47, 272 and 428% by d 8 and 144, 356, and 415% by d 16 in pigs fed the 0.5% ARA, 2.5% ARA, and 5% ARA diets, respectively, compared with the 0% ARA control pigs (P < 0.01). On d 16, ARA enrichment increased progressively with increasing dietary ARA supplementation from 0 to 2.5% but plateaued as dietary ARA rose to 5%. A similar pattern of ARA enrichment was observed in ileal mucosal phospholipids, but maximal enrichment in the ileum exceed that in the jejunum by >50%. As ARA increased, linoleic acid content decreased reciprocally. Although maximal enterocyte enrichment with EPA approached 20-fold by d 8, concentrations were only approximately 50% of those attained for ARA. Negligible effects on gross villus/crypt morphology were observed. These data demonstrate a dose-dependent response of intestinal mucosal phospholipid ARA concentration to dietary ARA with nearly full enrichment attained within 8 d of feeding formula containing ARA at 2.5% of total fatty acids and that supra-physiologic supplementation of ARA is not detrimental to growth.

Board-invited review: the use and application of distillers dried grains with solubles in swine diets

Distillers dried grains with solubles (DDGS) may be included in diets fed to pigs in all phases of production. The concentrations of DE and ME in DDGS are similar to those in corn. Phosphorus in DDGS is highly digestible to pigs and apparent total tract digestibility values of approximately 60% have been reported. The concentration of starch in DDGS is low (i.e., between 3 and 11%), but the concentration of fat in DDGS is approximately 10% and the concentrations of ADF, NDF, and total dietary fiber in DDGS are approximately 3 times greater than those in corn (9.9, 25.3, and 42.1%, respectively). The apparent total tract digestibility of dietary fiber is less than 50%, which results in reduced digestibility values for DM and energy in DDGS. The concentrations of most AA in DDGS are approximately 3 times greater than those in corn, but the standardized ileal digestibility of most AA is approximately 10 percentage units less than in corn. Nursery pigs from 2 to 3 wk postweaning, and growing and finishing pigs may be fed diets containing up to 30% DDGS without any negative impact on growth performance. However, the carcass fat in pigs fed diets containing DDGS has a greater iodine value than the carcass fat in pigs not fed DDGS. It may, therefore, be necessary to withdraw DDGS from the diet of finishing pigs during the final 3 to 4 wk before slaughter to achieve the desired pork fat quality. Lactating sows can also be fed diets containing up to 30% DDGS, and DDGS can replace all the soybean meal in diets fed to gestating sows without negatively affecting sow or litter performance. Inclusion of DDGS in diets fed to pigs may improve immune system activation, but more research is needed to elucidate the mechanisms responsible for these effects. Manure volume will increase when DDGS is included in the diets because of the reduced digestibility of DM in DDGS. Nitrogen excretion may also increase, but this can be prevented by the use of crystalline AA in diets containing DDGS. In contrast, P excretion can be reduced in diets containing DDGS if the total dietary concentration of P is reduced to compensate for the greater digestibility of P in DDGS. In conclusion, DDGS can be included in diets fed to growing pigs in all phases of production, beginning at 2 to 3 wk postweaning, in concentrations of up to 30% DDGS, and lactating and gestating sows can be fed diets containing up to 30 and 50%, respectively, without negatively affecting pig performance.

Synergistic effects of betaine and conjugated linoleic acid on the growth and carcass composition of growing Iberian pigs

An experiment was conducted to determine the efficacy of dietary betaine, CLA, or both as growth promotants and carcass modifiers in growing Iberian pigs. Twenty gilts (20 kg of BW) were individually penned and fed barley- and soybean meal-based diets (12% CP, 0.81% Lys, and 14.8 MJ of ME/kg of DM) containing either no added betaine or CLA (control), 0.5% betaine, 1% CLA, or 0.5% betaine + 1% CLA, at 95% of ad libitum energy intake. An additional group of 5 pigs was slaughtered at the beginning of the experiment to obtain the initial body composition. At 30 kg of BW, a balance experiment was conducted. At 50 kg of BW, pigs were slaughtered and viscera was removed and weighed. Betaine or CLA alone did not affect growth performance. However, betaine + CLA increased ADG (601 vs. 558 g, P = 0.03) and gain relative to ME intake (25.4 vs. 22.2 g/MJ, P = 0.03) compared with control pigs. Digestibility of nutrients and metabolizability of energy did not differ among diets (P = 0.46 to 0.75). Carcass protein, water, and lean deposition (g/d) increased (19.8, 24.2, and 23.4%, respectively, P < 0.01) in pigs fed betaine + CLA compared with control pigs. Similarly, protein deposition relative to ME intake increased by 28% in betaine + CLA-supplemented pigs (P < 0.05). Fat and mineral deposition did not differ among treatments. Carcass protein, water, and lean content (g/kg of carcass) of pigs fed betaine + CLA-supplemented diets tended to increase (P = 0.07 to 0.09) and carcass fat content tended to decrease (P = 0.09). Similarly, estimated composition of carcass gain was affected, such that water and lean content tended to increase (P = 0.06 to 0.08), whereas fat tended to decrease (P = 0.08) in pigs fed betaine + CLA-supplemented diets. Longissimus muscle area was not altered by treatments (P = 0.49). The liver of pigs fed betaine + CLA diets had increased weight (19%, P < 0.05) compared with control pigs. Overall, dietary supplementation of betaine + CLA increased ADG, protein, water, and lean deposition in growing Iberian gilts. There appears to be a synergistic action when betaine and CLA are used together.

Conjugated linoleic acid reduces body fat accretion and lipogenic gene expression in neonatal pigs fed low- or high-fat formulas

Childhood obesity is an increasing problem and may predispose children to adult obesity. Weight gain during infancy has been linked to excessive weight later in life. Conjugated linoleic acids (CLA) have been shown to reduce fat gain and body fat mass in animal models and in humans. The effects of CLA in a piglet model of human infancy have not been determined. The objective of this experiment was to examine the regulation of body composition and lipid metabolism in pigs fed low- and high-fat milk formulas supplemented with CLA. Twenty-four piglets were fed low- (3%) or high-fat (25%) diets with or without 1% CLA in a 2 x 2 factorial design. Formulas were fed for 16-17 d. Piglet body weight gains did not differ, although pigs fed the low-fat diets consumed greater amounts of diet. Piglets fed the high-fat formula accreted 50% more body fat during the feeding period than low-fat fed piglets and CLA reduced body fat accretion regardless of dietary fat content. Liver and muscle in vitro oxidation of palmitate was not influenced by dietary treatments. Adipose tissue expression of acetyl-CoA carboxylase-alpha and lipoprotein lipase were significantly reduced by CLA treatment. Overall, CLA reduced body fat accretion without influencing daily gain in a piglet model of human infancy. Results indicate that inhibition of fatty acid uptake and synthesis by adipose tissue, and not increased fatty acid oxidation in liver or muscle, were involved in reducing body fat gain.

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.

Interactive effect of ractopamine and dietary fat source on quality characteristics of fresh pork bellies1

Crossbred pigs (n = 216) were used to test the interaction, if any, of ractopamine (RAC) and dietary fat source on the characteristics of fresh pork bellies. Pigs were blocked by BW (77.6 +/- 6.5 kg) and allotted randomly to pens (6 pigs/pen). After receiving a common diet devoid of RAC for 2 wk, pens within blocks were assigned randomly to 1 of 4 treatments arranged in a 2 x 2 factorial design, with 5% fat (beef tallow vs. soybean oil) and RAC (0 vs. 10 mg/kg). At the conclusion of the 35-d feeding period, pigs were slaughtered at a commercial pork packing plant (average BW of 108.8 +/- 0.6 kg), and fresh bellies were captured during carcass fabrication. Neither RAC (P = 0.362) nor fat source (P = 0.247) affected belly thickness. Subjective (bar-suspension) or objective (compression test) measures of belly firmness were not (P > or = 0.148) affected by the inclusion of RAC in the diet; however, bellies from pigs fed soybean oil (SBO) were softer than those from pigs fed beef tallow (BT), as indicated by perpendicular (P < or = 0.005) and parallel (P < 0.001) suspensions. Moreover, bellies from BT-fed pigs required more (P = 0.096) force to compress 50% of their thickness than bellies from SBO-fed pigs (52.29 vs. 43.51 kg). Color (L*, a*, and b* values) of the belly lean and fat was not (P > or = 0.131) affected by RAC, and lean color was similar (P > or = 0.262) between fat sources; however, belly fat from BT-fed pigs was lighter (P = 0.030) and redder (P = 0.013) in color than belly fat from SBO-fed pigs. Bellies of SBO-fed pigs had greater (P < 0.001) proportions of PUFA and lower (P < 0.001) proportions of SFA and MUFA than belly fat from pigs fed BT. Regardless of the RAC inclusion level, PUFA:SFA and iodine values were lower in belly fat from pigs fed BT than SBO; however, within SBO-fed pigs, PUFA:SFA and iodine values were further increased by feeding RAC (RAC x fat source, P < 0.001). As expected, dietary fat source altered the fatty acid composition of fresh pork bellies, which subsequently impacted fresh belly firmness. Interestingly, including RAC in swine finishing diets exacerbated the effect of feeding SBO on pork fat polyunsaturation.

Fluctuation and criteria of porcine fat firmness

Fat quality, in particular, firmness is a main contributor to meat appearance, shelf life, taste, and human health. The current study was conducted to examine the fluctuation and criteria of porcine fat firmness. Several physiochemical methods were performed on 237 porcine perirenal fat samples that were obtained randomly from a commercial market. The relationship between perirenal fat and the middle subcutaneous fat layer was investigated to predict carcass fat quality. Each physiochemical property of the perirenal fat showed considerable variation as a 40-fold difference in firmness was observed between the most extreme samples. Differences between these extremes were 19°C in melting point, 0·0043 for refractive index, and 18 g per 100 g fatty acid methyl esters for saturated fatty acids (SFA) concentration. Strong curvilinear relationships were found between Instron and sensory firmness scores (R=0·90–0·96, no.=24). On the basis of these relationships, classification of the perirenal fats obtained from the commercial market was defined. Fats possessing firmness values of less than 7 N have undesirable fat quality, whereas fat samples with values greater than 16 N were not popular in the market. From these data, we conclude that fats of 7–16 N in firmness value were preferred by consumers. Firmness values of perirenal fat samples correlated significantly with the stearic acid (C18:0) and SFA concentrations of samples of the middle subcutaneous fat layer (r=0·68, 0·57, P<0·01). These results indicate that there are wide fluctuations in the porcine fat quality, and that fats ranging in Instron firmness values between 7 and 16 N are most acceptable to consumers. And, subcutaneous fat may prove to be a valuable indicator of whole body pork fat quality.

Conjugated linoleic acid and its effects on animal products and health in single-stomached animals

Conjugated linoleic acids (CLA) have been shown to have anti-carcinogenic, anti-obesity, anti-atherogenic and immunomodulatory functions. The basis for these effects has not been fully explained, but probably involves effects of CLA on eicosanoid metabolism, cytokine production and\or gene expression. The predominant isomer (85–90%) in the natural sources of CLA has thecis-9, trans-11 configuration. As interest in CLA grew and synthetic forms became available, the number of studies examining the effects of dietary CLA in rodents, human subjects and livestock has increased greatly. In the late 1990 s the observation that CLA had anti-obesity effects was reported. Subsequently, it was determined that this effect in mice could be attributed to thetrans-10, cw-12 isomer that, along with thecis-9,trans-11 isomer, predominates in the synthetic forms of CLA. The santi-obesity response varies in magnitude depending on species, and has not been consistent in non-rodents. In general, the response is greatest in mice and less or absent in other species. The basis for this lack of consistency is not clear and is unlikely to be accounted for by differences in the source of CLA. In the pig variation in body fat of animals may account for differences in responsiveness. There is no direct evidence of an anti-carcinogenic effect of CLA in human subjects or livestock. Indirect evidence fromin vitrostudies with cell lines, as well as epidemiological studies, suggest that CLA may be relevant as a natural anti-carcinogen. The immunomodulatory effects of CLA may have application in livestock production as an alternative to the use of feed antibiotics, or as a means of improving the response to vaccination and conferring disease resistance. The recent literature on the effects of CLA, with emphasis on its anti-obesity effects, is reviewed.

[Linoleic conjugated acid: current interest in human nutrition]

Conjugated linoleic acid (CLA) is a group of positional and geometric isomers of linoleic acid. The major dietary sources of CLA are meat from rumiants and dairy products. There are also foods enriched in CLA (by modification animal feed or addition of commercial CLA from cartamo oil). However, the major isomer of CLA in natural food is cis-9,trans-11 and commercial CLA contains approximately equal amounts of cis-9,trans-11 and trans-10,cis-12 isomers. Although CLA is minor component of the diet, at present CLA has provoked intense scientific research accompanied by an advertising boom. This is due to the potential health effects demonstrated in animal and cell culture experiments including effects on body composition, specially a reduction in body fat mass and anticarcinogenic, antidiabetogenic and immune modulating effects. The results obtained in human volunteers are limited and even sometimes contradictory. This review focuses on recently studies in humans. To draw conclusions on CLA's potential interest as a functional ingredient, additional studies are needed to clearly define optimal level of CLA intake, short and long term effects and side effects of each individual CLA isomer in order to determine its safety and efficacy.

Descriptive flavor analysis of bacon and pork loin from lean-genotype gilts fed conjugated linoleic acid and supplemental fat1

This study evaluated the combined effects of dietary CLA and supplemental fat (SF) source on organoleptic characteristics of bacon and pork loin samples in lean-genotype gilts (n = 144). Gilts (49.3 kg of BW) were randomly assigned to a 3 x 2 factorial design, consisting of SF [0% SF, 4% yellow grease (YG), or 4% tallow] and linoleic acid (LA; 1% corn oil or 1% CLA). Animals were slaughtered (113 kg) after a feeding period of 47 d. A trained sensory panel (n = 6 members) developed a flavor profile on commercially cured bacon samples (12 descriptors) and center-cut, boneless, pork loin chops (18 descriptors, using a 14-point, universal intensity scale). Bacon samples from pigs fed 4% SF were considered to have a sweeter flavor (4.07 +/- 0.07) than those fed 0% SF (3.89 +/- 0.07; P < 0.04). The intensity of salty flavor was greater in bacon samples from pigs fed LA (6.18 +/- 0.09) compared with those fed CLA (5.86 +/- 0.10; P < 0.04). The intensity of salty aftertaste of bacon was greater when LA was combined with YG (5.21 +/- 0.14; P < 0.07) or tallow (5.44 +/- 0.14; P < 0.01) than for LA alone (4.85 +/- 0.14, but SF combined with CLA was not different from CLA alone (fat x LA; P < 0.02). Sour flavor intensity tended to be lower in loin samples from pigs fed CLA than for those fed LA (1.60 vs. 1.73 +/- 0.06; P < 0.09). Samples from animals fed 4% tallow tended to have lower (P < 0.09) notes of astringent aftertaste (1.42 +/- 0.08) compared with those fed 0% SF (1.62 +/- 0.09) or 4% YG (1.66 +/- 0.09). Overall, the flavor differences for bacon and loin samples were minimal, with most means differing by 1 point or less on the 14-point intensity scale. The sensory panel results indicate consumer acceptance of bacon and pork products from pigs fed CLA will not likely differ from commodity pork products.

Conjugated linoleic acid evokes de-lipidation through the regulation of genes controlling lipid metabolism in adipose and liver tissue

Conjugated linoleic acid (CLA) is a unique lipid that elicits dramatic reductions in adiposity in several animal models when included at < or = 1% of the diet. Despite a flurry of investigations, the precise mechanisms by which conjugated linoleic acid elicits its dramatic effects in adipose tissue and liver are still largely unknown. In vivo and in vitro analyses of physiological modifications imparted by conjugated linoleic acid on protein and gene expression suggest that conjugated linoleic acid exerts its de-lipidating effects by modulating energy expenditure, apoptosis, fatty acid oxidation, lipolysis, stromal vascular cell differentiation and lipogenesis. The purpose of this review shall be to examine the recent advances and insights into conjugated linoleic acid's effects on obesity and lipid metabolism, specifically focused on changes in gene expression and physiology of liver and adipose tissue.

Effects of dietary factors and other metabolic modifiers on quality and nutritional value of meat

A number of technologies that increase feed efficiency and lean tissue deposition while decreasing fat deposition have been developed in an effort to improve profitability of animal production. In general, the mode of action of these metabolic modifiers is to increase muscle deposition while often simultaneously reducing fat deposition. However, there have been some concerns that the focus on increasing production efficiency and lean meat yield has been to the detriment of meat quality. The aim of this review is to collate data on the effects of these metabolic modifiers on meat quality, and then discuss these overall effects. When data from the literature are collated and subject to meta-analyses it appears that conservative use of each of these technologies will result in a 5-10% (0.3-0.5kg) increase in shear force with a similar reduction in perception of tenderness. However, it should be borne in mind that the magnitude of these increases are similar to those observed with similar increases in carcass leanness obtained through other means (e.g. nutritional, genetic selection) and may be an inherent consequence of the production of leaner meat. To counter this, there are some other metabolic factors and dietary additives that offer some potential to improve meat quality (for example immuncastration) and it is possible that these can be used on their own or in conjunction with somatotropin, approved β-agonists, anabolic implants and CLA to maintain or improve meat quality.

Dietary conjugated linoleic acid affects morphofunctional and chemical aspects of subcutaneous adipose tissue in heavy pigs

We investigated the in vivo effects of dietary conjugated linoleic acid (CLA) on subcutaneous adipose tissue from heavy pigs to clarify the involvement of possibly different causative effects in the established antiadipogenic effect of CLA. Pigs [n = 36; initial body weight, 106 kg live weight (LW)] were assigned to 1 of 2 LW-matched groups supplemented with either 0 or 0.75% of a CLA preparation containing 50% CLA isomers. The pigs were slaughtered at 155 kg LW and adipose tissue analyzed. CLA supplementation affected ash content, and decreased iodine values (P < 0.01) and adipocyte size (P < 0.05). The fat content of adipose tissue was lower (P < 0.05) in females than castrated males, and females had smaller (P < 0.01) adipocytes than castrated males. Neither CLA nor sex influenced adipocyte lipid droplet diameter or the extent of lipid peroxidation as determined by quantitation of Schiff's histochemical reaction. NADPH-diaphorase was not influenced by CLA treatment. Preadipocyte proliferation rates were lower in pigs fed CLA (P < 0.05), whereas the number of adipocyte apoptotic nuclei was greater (P < 0.05). Preadipocyte proliferation was also greater (P < 0.05) in females than castrated males. Neuronal and endothelial nitric oxide synthase activities did not differ between groups in adipose tissue vessels, but inducible nitric oxide synthase expression in adipocytes was lower in pigs fed CLA (P = 0.05). These findings suggest that the antiadipogenic effect of CLA in heavy pigs is not a direct effect but may occur by downregulation of a NO-mediated lipolytic pathway.