BACKGROUNDOne promising strategy for reducing human salmonellosis induced by Salmonella Enteritidis is to supplement animal diets with natural feed additives such as mannan oligosaccharides (MOSs).OBJECTIVEWe sought to investigate the potential role of Salmosan (S-βGM), an MOS product extremely rich in β-galactomannan, in preventing epithelial barrier function disruption induced by S. Enteritidis colonization in an in vitro model of intestinal Caco-2 cells in culture.METHODSDifferentiated Caco-2 cells were incubated for 3 h with S. Enteritidis at a multiplicity of infection of 10 in the absence or presence of 500 μg S-βGM/mL. Paracellular permeability (PP) was assessed by transepithelial electrical resistance (TER), d-mannitol, and fluorescein isothiocyanate-dextran (FD-4) flux. Tight junction proteins and cytoskeletal actin were also localized by confocal microscopy. Reactive oxygen species (ROS) and lipid peroxidation products were evaluated. Scanning and transmission electron microscopy were used to visualize S. Enteritidis adhesion to, and invasion of, the Caco-2 cell cultures.RESULTSCompared with controls, TER was significantly reduced by 30%, and d-mannitol and FD-4 flux were significantly increased by 374% and 54% in S. Enteritidis-infected cultures, respectively. The presence of S-βGM in infected cultures induced total recoveries of TER and FD-4 flux to values that did not differ from the control and a partial recovery of d-mannitol flux. These effects were confirmed by immunolocalization of actin, zonula occludens protein 1, and occludin. Similar results were obtained for Salmonella Dublin. The protection of S-βGM on PP in infected cultures may be associated with a total recovery of ROS production to values that did not differ from the control. Moreover, S-βGM has the capacity to agglutinate bacteria, leading to a significant reduction of 32% in intracellular S Enteritidis.CONCLUSIONThe results demonstrate that S-βGM contributes to protecting epithelial barrier function in a Caco-2 cell model disrupted by S. Enteritidis.

The effect of dietary crude protein (CP) reduction, supplementation with arginine or leucine on intramuscular fat (IMF) content was evaluated in (Landrace × Duroc) × Pietrain pigs. One-hundred and eight barrows (67 ± 4 kg) were assigned to six diets (n=6 pens of 3 pigs each): four normal CP diets containing 16% CP from 60 to 90 kg and 13% CP from 90 to 115 kg live weight (normal protein; normal protein high Arg, normal protein high Leu or normal protein high Arg and Leu) and two low CP diets containing 14% CP from 60 to 90 kg and 11.8% CP from 90 to 115 kg live weight (with or without supplementation of both amino acids). The high Leu and Arg diets were supplemented to obtain ratios of standard ileal digestible Leu/Lys and Arg/Lys of 4 and 2, respectively. While feed to gain ratio tended to increase (p<0.05), final weight (p<0.01), average daily feed intake (ADFI) (p<0.05) and average daily gain (ADG) (p<0.01) were reduced in animals fed low-protein diets supplemented with Arg and Leu compared to the ones fed low-protein diet unsupplemented. Marbling and IMF content in loin were reduced when Arg was supplemented (p<0.05) in normal protein diets. Supplementing these diets with Arg also reduced belly weight (p<0.01) and increased lean meat percentage (p<0.05). Contrary to the initial hypothesis, reduction of CP or dietary supplementation with Leu had no effect on IMF content and supplementation with Arg reduced it.

EFSA Supporting PublicationsVolume 13, Issue 2 1001E External scientific reportOpen Access Preparatory work to support the re-evaluation of technological feed additives (OC/EFSA/FEED/2013/01) N. Tous, N. Tous IRTASearch for more papers by this authorJ. Brufau, J. Brufau IRTASearch for more papers by this authorA. Pérez-Vendrell, A. Pérez-Vendrell IRTASearch for more papers by this authorB. Vilà, B. Vilà IRTASearch for more papers by this authorM. Francesch, M. Francesch IRTASearch for more papers by this authorD. Torrallardona, D. Torrallardona IRTASearch for more papers by this authorM. Castellari, M. Castellari IRTASearch for more papers by this authorJ. Diogene, J. Diogene IRTASearch for more papers by this authorM. Viñas, M. Viñas IRTASearch for more papers by this authorV. Castell, V. Castell ACSASearch for more papers by this authorE. Vicente, E. Vicente ACSASearch for more papers by this authorI. Badiola, I. Badiola ACSASearch for more papers by this authorE. Esteve-Garcia, E. Esteve-Garcia ACSASearch for more papers by this author N. Tous, N. Tous IRTASearch for more papers by this authorJ. Brufau, J. Brufau IRTASearch for more papers by this authorA. Pérez-Vendrell, A. Pérez-Vendrell IRTASearch for more papers by this authorB. Vilà, B. Vilà IRTASearch for more papers by this authorM. Francesch, M. Francesch IRTASearch for more papers by this authorD. Torrallardona, D. Torrallardona IRTASearch for more papers by this authorM. Castellari, M. Castellari IRTASearch for more papers by this authorJ. Diogene, J. Diogene IRTASearch for more papers by this authorM. Viñas, M. Viñas IRTASearch for more papers by this authorV. Castell, V. Castell ACSASearch for more papers by this authorE. Vicente, E. Vicente ACSASearch for more papers by this authorI. Badiola, I. Badiola ACSASearch for more papers by this authorE. Esteve-Garcia, E. Esteve-Garcia ACSASearch for more papers by this author First published: 26 February 2016 https://doi.org/10.2903/sp.efsa.2016.EN-1001 The present document has been produced and adopted by the bodies identified above as authors. This task has been carried out exclusively by the authors in the context of a contract between the European Food Safety Authority and the authors, awarded following a tender procedure. The present document is published complying with the transparency principle to which the Authority is subject. It may not be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the authors. Published date: 26 February 2016 Question number: EFSA-Q-2016-00147 AboutPDF ToolsExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL References Commission Regulation (EC) No 429/2008 of 25 April 2008 on detailed rules for the implementation of Regulation (EC) No 1831/2003 of the European Parliament and of the Council as regards the preparation and the presentation of applications and the assessment and the authorisation of feed additives. OJ L 133, 22.5.2008, 1– 65. EFSA (European Food Safety Authority), 2008a. Guidance for the preparation of dossiers for the reevaluation of certain additives already authorised under Directive 70/524/EEC. The EFSA Journal 2008, 779, 1– 9. EFSA (European Food Safety Authority), 2008b. Technical guidance for assessing the safety of feed additives for the environment. The EFSA Journal 2008, 842, 1– 28. EFSA FEEDAP Panel (EFSA Panel on Additives and Products or Substances used in Animal Feed), 2011a. Guidance on the assessment of the additives intended to be used in pets and other non food-producing animals. EFSA Journal 2011; 9(2):2012, 3 pp. doi:10.2903/j.efsa.2011.2012 EFSA FEEDAP Panel (EFSA Panel on Additives and Products or Substances used in Animal Feed), 2011b. Technical Guidance: Tolerance and efficacy studies in target animals. EFSA Journal 2011; 9(5):2175, 15 pp. doi:10.2903/j.efsa.2011.2175 EFSA FEEDAP Panel (EFSA Panel on Additives and Products or Substances used in Animal Feed), 2012a. Guidance for the preparation of dossiers for technological additives. EFSA Journal 2012; 10(1):2528, 23 pp. doi:10.2903/j.efsa.2012.2528 EFSA FEEDAP Panel (EFSA Panel on Additives and Products or Substances used in Animal Feed), 2012b. Guidance for the preparation of dossiers for additives already authorised for use in food. EFSA Journal 2012; 10(1):2538, 4 pp. doi:10.2903/j.efsa.2012.2538 EFSA FEEDAP Panel (EFSA Panel on Additives and Products or Substances used in Animal Feed), 2012c. Guidance on studies concerning the safety of use of the additive for users/workers. EFSA Journal 2012; 10(1):2539, 5 pp. doi:10.2903/j.efsa.2012.2539 Regulation (EC) No 1831/2003 of the European Parliament and of the Council of 22 September 2003 on additives for use in animal nutrition. OJ L268, 18.10.2003, 29– 43. Volume13, Issue2February 20161001E ReferencesRelatedInformation

Salmonella enterica serovar Enteritidis is one of the leading causes of food-borne salmonellosis in humans. Poultry is the single largest reservoir, and the consumption of incorrectly processed chicken meat and egg products is the major source of infection. Since 2006, the use of antibiotics as growth promoters has been banned in the European Union, and the dietary inclusion of β-galactomannans (βGM) has become a promising strategy to control and prevent intestinal infections. The aim of this study was to investigate the effect of various βGM-rich products on intestinal morphology in chickens challenged with Salmonella Enteritidis. To assess this effect, a total of 280 male Ross 308 chickens were studied (40 animals per treatment housed in 5 cages). There were 7 treatments, including controls: uninoculated birds fed the basal diet (negative control) and inoculated birds fed the basal diet (positive control) or the basal diet supplemented with Salmosan (1 g/kg), Duraió gum (1 g/kg), Cassia gum (1 g/kg), the cell walls of Saccharomyces cerevisiae (0.5 g/kg), or the antibiotic colistine (0.8 g/kg). The birds were fed these diets from the d 1 to 23, except the animals in the colistine group, which were fed the diet containing the antibiotic only from d 5 to 11. The inoculated animals were orally infected on d 7 with 10(8) cfu of Salmonella Enteritidis. Bird performance per replicate was determined for the whole study period (23 d), and the distal ileum and cecal tonsil of 5 animals per treatment (1 animal per replicate) were observed at different magnification levels (scanning electron, light, and laser confocal microscopy). In the images corresponding to the treatments containing βGM we observed more mucus, an effect that can be associated with the observation of more goblet cells. Moreover, the images also show fewer M cells, which are characteristic of infected animals. Regarding the morphometric parameters, the animals that received Duraió and Cassia gums show greater (P = 0.001 and P = 0.016, respectively) villus length compared with the animals in the positive control, thus indicating the capacity of these products to increase epithelial surface area. However, no effect (P > 0.05) on microvillus dimensions was detected. In conclusion, the results obtained indicating the beneficial effects of these βGM on intestinal morphology give more evidence of the positive effects of these supplements in poultry nutrition.

Nutritional strategies like reduction of dietary vitamin A have been proposed with the aim of increasing intramuscular fat (IMF) and improving the meat quality. The purpose of the study was to evaluate if reduction of dietary vitamin A would increase IMF, without affecting backfat deposition and pig performance parameters. Forty eight barrows were fed diets with different vitamin A levels: without supplemental vitamin A (0 IU vitamin A /kg; n=16), a level close to the requirement of NRC (1998) (1250 IU vitamin A/kg; n=16) or a level typically used in commercial formulation (5000IU vitamin A/kg; n=16). The treatment without supplemental vitamin A did not affect growth performance parameters, only a trend to increase final body weight was observed when compared with animals fed with vitamin A in the diet. However, reduced perirenal fat and a trend to increase muscle depth between the 3th and 4th ribs was observed in the animals fed the diet with no supplemental vitamin A. These results suggested a reduction of fatness when vitamin A was omitted in the diet, contrary to the initial hypothesis. Intramuscular fat content was not affected by the reduction of the dietary vitamin A levels below the requirements; in fact the trend was opposite to the original hypothesis. The content of retinol in the liver was increased when the animals were fed higher levels of dietary vitamin A but animals fed without vitamin A diet also produced retinol, although in a reduced amount, which could explain the lack of effects of vitamin A reduction on performance. When comparing 5000IU/kg with 0IU/kg diets, only a trend in reduced expression of PPARα without impaired modification on fat content was observed in longissimus muscle. From this study, it can be concluded that omitting supplemented vitamin A does not affect performance, decreases perirenal fat and possibly overall fat deposition, without a significant reduction on IMF, contrary to the original hypothesis.

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Intramuscular fat is an important quality trait in pork. Lysine and protein have been reported to influence this trait, but most studies have modified both factors simultaneously. In this study, the effects of dietary Lys and protein were investigated in finishing pigs to determine if either of the 2 factors alone or in combination influence the deposition of intramuscular fat. One hundred and four barrows (Landrace × Duroc) were fed 1 of 4 experimental diets, including control protein-control Lys (CPCL), control protein-low Lys (CPLL), low protein-control Lys (LPCL), and low protein-low Lys diets (LPLL) with 10 pens per treatment and 2 or 3 pigs per pen. Pigs fed CPLL showed a trend to decrease feed efficiency (P < 0.10) compared with those fed CPCL, but pigs fed LPLL performed similarly to the CPCL pigs, indicating that CP levels can be reduced to 12% for pigs between 62 and 97 kg and to 9.8% afterward without negative effects on performance. In the longissimus thoracis, intramuscular fat increased in pigs fed LPCL or CPLL (P < 0.05) compared with CPCL. In the semimembranosus muscle, intramuscular fat was reduced in pigs fed LPLL compared with those fed CPLL (P < 0.05), and the same trend was observed in the longissimus thoracis (P < 0.10). Dietary protein reduction tended to increase back fat thickness (P < 0.10) and reduced SFA and MUFA (P < 0.05) and PUFA, particularly in subcutaneous fat (P < 0.05), whereas the effect on MUFA in the longissimus thoracis was less pronounced. A reduction of n-3 FA (P < 0.05) and PUFA (P < 0.01) in the semimembranosus muscle and in the liver, respectively, was observed when the level of dietary protein was reduced. These results indicate that the effect of a reduction of dietary protein and Lys on growth and intramuscular fat is not independent, and reduction of protein, while maintaining Lys, may improve meat quality without impairing performance.

The aim of this study was to investigate underlying mechanisms of dietary conjugated linoleic acid (CLA) on lipid metabolism in various tissues of pigs. Sixteen gilts (73 ± 3 kg) were fed a control (containing sunflower oil) or an experimental diet in which 4% of sunflower oil was replaced by CLA, and slaughtered at an average BW of 117 ± 4.9 kg. Transcription of peroxisome proliferator-activated receptor alpha (PPARα), peroxisome proliferator-activated receptor gamma (PPARγ), fatty acid synthase (FAS), sterol regulatory element binding protein (SREBP1), acetyl-CoA carboxylase (ACC), lipoprotein lipase (LPL), delta-6-desaturase (D6D), and stearoyl CoA desaturase (SCD) were determined by real-time PCR in longissimus thoracis (LT) and semimembranosus (SM) muscles, LT subcutaneous and SM intermuscular fat, and in the liver. Fatty acid (FA) composition was analyzed using gas chromatography in these tissues, except for SM intermuscular fat. Dietary CLA increased PPARγ in LT muscle (P < 0.05), whereas CLA reduced PPARα transcription in all tissues studied (P < 0.05) with the exception of intermuscular fat. Transcription of genes related to FA synthesis was reduced by CLA in SM muscle and liver (SREBP1, both P < 0.1; ACC, P < 0.01 in SM; and FAS, P < 0.01 in liver), whereas CLA reduced (P < 0.05) LPL and D6D transcriptions in SM muscle and reduced (P < 0.05) SCD in liver but increased (P < 0.05) SCD in LT muscle and intermuscular fat. Saturated FA were increased in all studied tissues (P < 0.01), while monosaturated and polyunsaturated FA were reduced in a tissue-specific way by CLA. It was concluded that dietary CLA affected transcription of genes and fat metabolism in a tissue-specific manner.

Salmonella is presently one of the microorganisms of higher concern for food safety in poultry products. The present study examined the effect of feeding galactomannans from carob bean gum on nutrient digestibility and performance in chickens, and on the prevalence of Salmonella enterica var. Enteritidis in challenged animals. Four experiments were performed with either broiler or leghorn chickens, challenged with 106CFU (colony-forming units) of S. Enteritidis at 1day of life, and feeding carob bean gum at different concentrations (25, 50 or 100g/kg, depending on the experiment), alone or in combination with β-mannanase, cellulase or α-galactosidase at 8.3U/g; or feeding D-mannose at 25g/kg, or depolymerized carob bean gum or guar gum at 100mg/kg. Trials lasted 3or 4weeks. Body weight and feed intake were determined and feed conversion ratio calculated (feed:gain). Faeces were collected during the last week on trial for evaluation of nutrient balance (energy, lipids and protein), using chromium oxide as inert marker. Viscosity of the ileal content was also determined at the end of the second experiment. Salmonella presence in caeca was determined two and 3weeks after challenge. Performance and nutritive value of diets were impaired in birds fed carob bean gum, with higher effect at higher inclusion rates. D-mannose impaired performance variables only whereas depolymerized gums did not affect bird performance or nutritive value of the diets. Of the enzymes tested, only β-mannanase significantly decreased the viscosity of the intestinal contents of birds fed carob bean gum and partly counteracted the impairment in bird performance and the reduction in the nutritive value of the diets. The number of Salmonella-positive birds varied among experiments and was lower in the third week post-challenge compared to the second week post-challenge. However, the reduction in the number of Salmonella-positive birds was more constant and marked when carob bean gum was present in the diet. The inclusion of carob bean gum in the diet of chickens at the high concentrations used in the present experiment reduced the presence of Salmonella in challenged birds, but it also impaired performance and nutrient digestibility. These impairments were partially counteracted by the addition of β-mannanase to the diet. Carob bean gum might be used to reduce the incidence of Salmonella in chickens, while its negative effects on performance and nutrient digestibility could be counteracted by β-mannanase.

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 objective was to evaluate the effect of ZnO-Functionalised-Sepiolite (ZnO-Sepiolite) to fulfil Zn requirements and health status of weaning piglets. Pre-starter Basal Diet (BD, corn–soybean based, from weaning till 14days on trial) was calculated to provide 27mg Zn/kg feed from raw materials and had no added ZnO and no antibiotics or organic acids. Treatments during pre-starter period were: 1) BD+90% of NRC Zn requirements completed with ZnO (ZnO90); 2) BD+90% of NRC Zn requirements completed with ZnO-Sepiolite (ZnOS90); 3) BD+3000mg ZnO/kg of diet (ZnO3000); 4) BD+150mg added Zn/kg diet from ZnO-Sepiolite (ZnOS150). The starter feed (corn–soybean based, from 14 till 31days on trial) was common for all piglets, and met 90% NRC Zn requirements by adding ZnO. Diarrhea affected more than 50% of the animals of ZnO90, ZnOS90 and ZnOS150, and 33% of the ZnO3000 animals. Animals from ZnOS90 tended (P<0.10) to improve Gain to Feed ratio (G:F) compared to animals from ZnO90 (0.830kg/kg vs. 0.811kg/kg for G:F). Performance of animals from ZnO3000 was not significantly different from the other treatments, and was numerically similar to animals from ZnOS90. The inclusion of ZnO at 3000mg/kg of feed in the pre-starter period numerically decreased P in serum at the end of this period, with no effect on Ca level; normal levels were restored after 2weeks of feeding the same levels of Zn than other animals. Animals fed ZnO-Sepiolite diets had numerically higher serum Ca than ZnO90 and ZnO3000 at 12days and higher than ZnO90 at 28days. Serum Zn levels were significantly higher for ZnO3000 than the other treatments.

Benefits from probiotic micro-organisms have been recognised for over 100 years, and as being useful in poultry for 50 years. Fuller (1989) redefined probiotics as 'a live microbial feed supplement which beneficially affects the host animal by improving its intestinal microbial balance'. Benefits derived from this improved intestinal microbial balance could be reflected in performance or prevention of pathogen colonisation. Probiotic micro-organisms use in poultry production has been widely accepted and new opportunities arose from the 2006 EU ban on antimicrobial growth promoters. The majority of microbial products for compound feeds are made up from a relatively small number of micro-organisms that are normally present in the GI tract. They include non-sporulated bacteria, sporulated bacteria, fungi or yeasts; and presented from single to multi-strain products. A review on the proposed modes of action is presented including recent approaches to quorum sensing interference.

Two experiments were performed to determine the best strategy of use of the product TRACTcare® 4P (ITPSA) (TC, specific immunoglobulin-rich egg yolk powder within an energetic fatty acid matrix) in piglets from weaning and for 6weeks, in diets without or with inclusion of antibiotics. Each trial was performed with 144 piglets in 24 pens, in a completely randomized design blocked by initial body weight. Feeds were formulated according to animal requirements in two periods. In the first trial no antibiotics were included in the feeds and no room disinfection from previous trial was performed; treatments were: 1) Negative control (NC); 2) NC+TC on top of the feed within the hopper for the first 3days on trial (30g/pig×day), and eventually if diarrhea appeared (TCOT); 3) NC+TC ad libitum provided in an extra hopper within the pen (TCAL); and 4) NC+TC at 5g/kg added to the feed in the mixer (TC5). In the second trial, treatments were: 1) Positive control: basal diet that included 250mg/kg amoxiciline (BD)+100mg/kg colistine (AC); 2) BD+2g/kg TC (TC2A); 3) BD+5g/kg TC (TC5A); and 4) BD+8g/kg TC (TC8A). In diets without antibiotics, the product TC at 5g/kg in the feed numerically improved BW by 8% compared to Control animals, while G:F was almost identical between both groups. When antibiotics were used in the feed, replacement of colistin at 100mg/kg for TC at 2g/kg in feed numerically improved the performance compared to Positive control animals (for the whole trial period ADG 8% better: 390g vs. 361g; G:F 1% better: 0.748kg/kg vs. 0.742kg/kg), possibly due to the stimulation of feed consumption at weaning. In both trials, the lower number of dead and culled animals from TC5 and TC2A together with higher BW represented an advantage over Control treatments of 6% to 10% animals more and 15% to 17% total BW more at the end of the trial.

The effect of continuously feeding the probiotic microorganism Toyocerin to birds inoculated with Salmonella Enteritidis field-isolated strains on Salmonella Enteritidis prevalence, and performance variables were studied in 2 experiments. The experiments were performed with 1) broiler chickens in floor pens until slaughter 42 d of age, challenge was performed on d 3, 7, or 14 with 2 x 10(6) cfu per chick, and 2) Single Comb White Leghorn chickens in cages until 28 d of age, challenge was performed on d 7 with 10(8) cfu per chick. The inclusion of Toyocerin in feed of inoculated broiler chickens did significantly (P < 0.05) improve ADG (by 3.4 g), BW (by 141 g), and feed conversion ratio (by -0.060 kg/kg) at the end of the trial at 42 d compared with inoculated and untreated birds. At the end of the trial at 42 d, the slaughter age, 42% of untreated birds were still positive for Salmonella, whereas Salmonella was not detected in Toyocerin-treated birds. In Leghorn chickens, at 3 wk after inoculation (the end of the trial), only 38% of birds from the Toyocerin-treated groups were Salmonella-positive, whereas 63% of birds were still Salmonella-positive in the untreated control treatment. No significant differences were detected in performance variables in Leghorn chickens. The results of the present experiments indicate that feeding Toyocerin reduced the prevalence of Salmonella in poultry and in the case of broiler chickens also significantly improved performance variables at slaughter age.

In the present work, natural red pigment from Capsicum annum was compared to the synthetic canthaxanthin for broiler skin coloration. Two trials were performed in order to obtain the efficiency ratio between both red pigments. In the first trial, 3 increasing levels of canthaxanthin (3, 6 and 9 ppm) were compared to 3 increasing levels of natural red pigments at efficiency ratios of 1.5x (4.5, 9.0 and 13.5 ppm of red xanthophylls) and 2.0x (6.0, 12.0 and 18.0 ppm of red xanthophylls); yellow base was common between red pigment sources (9, 18 and 27 ppm of yellow xanthophylls). In the second trial, the same 3 increasing levels of canthaxanthin (3, 6 and 9 ppm) were compared with 6 increasing levels of natural red pigments at efficiency ratios of 2.5x (7.5, 11.3, 15.0, 18.8, 22.5 and 26.3 ppm of red xanthophylls) and 3.0x (9.0, 13.5, 18.0, 22.5, 27.0 and 31.5 ppm of red xanthophylls); yellow base was common between red pigments. Foot pad colour was determined in vivo and post mortem with a Minolta CR-300 colorimeter, shank colour was assessed post mortem by the Roche Yolk Colour Fan. In both trials, at common yellow levels in the diet, higher level of natural red pigments achieved higher level of coloration. The colour achieved by the canthaxanthin pigment were higher than for the natural red pigment in the first trial, and the efficiency ratio determined by regression was between 2.2x and 3.0x depending on the variable studied. In the second trial, differences between natural red pigment and canthaxanthin were not significant or minimal at common yellow levels in the diet. The efficiency ratio determined by regression confirmed the results from the first trial. As a general conclusion, natural red pigments may be used in combination with natural yellow pigments to confer the orange hue desired in broiler skin, with redder coloration at higher levels of inclusion.

1. Two experiments were designed to study the influence of free fatty acid content and degree of saturation of free fatty acids and neutral fat on digestibility of added fats and fatty acids. Sunflower oil and tallow were used as neutral fats, and palmitic, stearic, oleic and linoleic acids as free fatty acids. Fat inclusion was 80 g/kg and mixtures of each fat and each free fatty acid were prepared in the proportions 100:0, 70:30 and 40:60. 2. Experimental diets were evaluated for fat and fatty acid digestibilities with broiler chickens at 21 d of age. The metabolisable energy of fat was calculated from the product of digestibility and gross energy. Increasing concentrations of saturated free fatty acids decreased the ME of added fat, whereas unsaturated free fatty acids did not significantly affect the ME value of added fat. 3. Digestibilities of individual fatty acids were analysed by linear regression with rate of inclusion of free fatty acid in the fat blend: palmitic and stearic acids gave a negative slope, whereas oleic and linoleic acids gave a slope not statistically different from zero. Because slopes for saturated fatty acids did not differ between the sunflower oil and tallow treatments, synergism between unsaturated and saturated fatty acids was not detected.

1. Using a multi-rate assay, 3 commercial acid oils (sunflower, soyabean and tallow) were evaluated for AMEn and added fat digestibility with broiler chicks, at 11, 25, 39, 53 and 60 d of age. The regression equations of AMEn values or ME of available fat on rate of inclusion of fat were calculated.2. Significance was achieved for linear regression but not for quadratic regression in both variables; neither rate of inclusion nor age of birds (except for tallow acid oil at 25 d) significantly affected the AMEn or ME of fat. Metabolisable energy of fat (on a dry matter basis) calculated from combined linear regression equations was 19.14 MJ/kg for sunflower acid oil, 18.09 MJ/kg for tallow acid oil and 27.94 Mj/kg for soyabean acid oil. Differences between sunflower and soyabean acid oils were attributed to Variations in unsaponifiable and non-eluted material of both fats.3. Abdominal fat pad weight and its relationship to carcase weight were also studied with birds slaughtered at 67 d of age. Chicks given tallow acid oil deposited larger amounts of abdominal fat, and this deposition was directly related to the rate of inclusion of acid oil in the diet.