M. D. Baucells

Dietary Polyunsaturated Fat Reduces Skin Fat as Well as Abdominal Fat in Broiler Chickens

The aim of this study was to determine the effect of different dietary fatty acid profiles on the main fat depots of broiler chickens: skin including s.c. fat (SK) and abdominal fat pad (AF). One hundred forty-four female broiler chickens were fed a low-fat diet (B; 0.5% of added fat) or diets supplemented with 10% of tallow (T), sunflower oil rich in oleic acid (SOO), sunflower oil rich in linoleic acid (SOL), linseed oil rich in linolenic acid (LO), or a mix of fats (M: 55% of T + 35% of LO + 10% SOL) that contained one-third each of saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids. The animals were housed in 36 cages and were randomly distributed into 6 dietary treatments with 6 replicates each. Experimental diets were evaluated for apparent total fatty acid availability and AME. On d 42, birds were slaughtered to determine the weight of AF and SK and fatty acid profile. Regarding the diets containing 10% added fat, the highest saturated diet (T) resulted in the lowest values of apparent total fatty acid availability and percentage of AME. Animals fed the most polyunsaturated diet (LO) had a lower SK deposition than those fed the saturated diet, on both an absolute (LO: 145 vs. T: 159 and M: 168 g; P < 0.001) and a relative basis (LO: 6.94 vs. T: 7.39 and M: 7.52 g/100 g of BW; P < 0.001). Furthermore, the lowest AF depot was observed in the LO diet (LO: 26.3 g vs. T: 37.6 and M: 39.9 g; P < 0.001). The added fat treatments caused significant but similar changes in fatty acid profile of both studied tissues. In conclusion, feeding broiler chickens polyunsaturated fatty acids, in comparison to dietary saturated fatty acids, reduced the amount of both AF and SK by approximately 30 and 9%, respectively.

Effects of dietary concentration and degree of polyunsaturation of dietary fat on endogenous synthesis and deposition of fatty acids in chickens

1. Two experiments were performed to assess the effect of different amounts of dietary polyunsaturated fatty acids (PUFA) on fatty acid composition of chickens. The contribution of de novo fatty acid synthesis to fatty acid profile was also estimated. 2. In trial 1, different fat sources were blended in different ratios allowing a gradient of dietary PUFA (from 15 to 61 g/kg), keeping added fat constant (9%). In trial 2, PUFA-rich oil was added at increasing inclusion rates (2, 4, 6 and 8%), achieving a dietary PUFA content ranging between 27 and 59 g/kg. 3. Increasing dietary PUFA inclusion resulted in an increase in PUFA deposition, with higher efficiency when dietary fat also provided saturated (SFA) and monounsaturated (MUFA) fatty acids (trial 1). 4. Increasing dietary PUFA in both trials resulted in a decrease in SFA and MUFA concentration in the whole body. 5. The estimated deposition of fatty acids from de novo synthesis was reduced when dietary fat content increased from 0 to 10%, varying between 35·34 and 17·66% for SFA and between 52·70 and 7·01% for MUFA in the whole body. The greater variation range for the MUFA supports the existence of a mechanism maintaining the SFA: (MUFA + PUFA) ratio within a specific range in biological membranes.

Increased sow nutrition during midgestation affects muscle fiber development and meat quality, with no consequences on growth performance.

Pregnant sow nutrition has potential effects on the muscle fiber development of progeny in utero. A total of 199 Landrace x Large White sows from parities 0 to 6 and their offspring were used to evaluate the effects of increasing the feeding amount during midpregnancy on the muscle tissue, growth performance, and meat quality of the progeny. The experiment was divided into 2 study replicates, and in each replicate, sows were assigned to 1 of the 2 treatments: 1) sows in the control group (C sows) were fed 2.5 to 3.0 kg/d (feed: 12.1 MJ of ME/kg and 0.62% lysine) throughout gestation; and 2) sows in the high group (H sows) received an extra feed allowance of 1.5 kg/d for gilts and 2.0 kg/d for multiparous sows above the C amount from d 45 to 85 of gestation (period of secondary muscle fiber formation). Sow backfat was recorded on d 40 and 85 of gestation. Sow performance (litter size and piglet BW) at farrowing and on d 18 of lactation was measured. At weaning, pigs were divided into 5 BW groups/treatment, and progeny growth performance was measured during the nursery (n = 958) and the growing-finishing (n = 636) periods. At slaughter, carcass and meat quality traits (lean content, main cut weight, pH, Minolta color, and drip loss) were recorded from the second lightest group at weaning (BW group 4; n = 90), and samples from the longissimus thoracis muscle were taken to study muscle fiber characteristics (n = 70). The extra nutrition from d 45 to 85 of gestation did not lead to differences in litter size or piglet BW at farrowing and on d 18 of lactation. Pigs born to H mothers had fewer muscle fibers and fewer estimated primary and secondary fibers than did pigs born to C mothers (P < 0.05). However, postnatal growth performance was not consistently affected by the maternal treatment. The smaller number of muscle fibers found in the H group of pigs was associated with fewer type IIB fibers (P < 0.05) with greater cross-sectional areas (P < 0.10), which might be related to the significantly greater meat pH at 24 h postmortem and the smaller L* (lightness) values recorded in the H group of pigs. Results from the present study confirm the existence of effects of maternal nutrition on fetal development, at least in terms of muscle tissue development and meat quality, although with no beneficial effects were found for the postnatal growth performance of the progeny.

Utilization of different fats and oils by adult chickens as a source of energy, lipid and fatty acids

Abstract Sixty adult Warren roosters approximately 1 year old, randomized in individual cages, were fed a basal diet with or without 4% added fat. Nine fats and oils were evaluated: tallow (T1 and T2); tallow + soybean acid oil (50:50, TSAO); palm oil (PO); palm oil + soybean acid oil (50:50, PSAO); soybean acid oil (SAO); lard (L); soybean oil (SO); and linseed oil (LO). Soybean lecithin was included at 50 g kg −1 in T2. Experimental diets were evaluated for apparent fat availability (AFA), apparent availability of individual fatty acid (AAFA) and apparent metabolizable energy (AME). The AFA and AAFA values for added fats and oils were derived from those obtained for the basal diet and those obtained for the fat-supplemented diets, by difference, assuming the utilization of fat and fatty acid in the basal diet to be constant. The AME values of added fats and oils were calculated as the product of their AFA values and their gross energy values. In addition, the AME of added fats was calculated by substitution from the AME values of the basal diet and the fat-supplemented diets. The AFA and AME of added fats and oils ranged from 873 to 1013 g kg −1 and 33.5 to 40.2 MJ kg −1 , respectively. The addition of soybean lecithin to tallow did not affect the nutritive value of this animal fat. The nutritive value of added fats was more influenced by their free fatty acid content (FFA) and non-nutritive fraction than by their degree of saturation. SAO, with high free fatty acids and unsaponifiable contents, resulted in the lowest values for AME and AFA, but both measurements increased significantly when it was blended with T1 or PO. The AME values of experimental diets supplemented with different fats and oils were equivalent.

High Levels of Dietary Unsaturated Fat Decrease α-Tocopherol Content of Whole Body, Liver, and Plasma of Chickens Without Variations in Intestinal Apparent Absorption

An experiment was designed to assess the effect of dietary unsaturated fat inclusion level on alpha-tocopherol apparent absorption and deposition in broiler chickens at 2 ages (20 and 39 d). The dietary fat was a mixture of linseed and fish oil, rich in polyunsaturated fatty acids (PUFA). The experimental treatments were the result of 4 levels of supplementation with alpha-tocopheryl acetate (0, 100, 200, and 400 mg/kg; E0, E100, E200, and E400 treatments, respectively) and 4 dietary oil inclusion levels (2, 4, 6, and 8%; O2, O4, O6, and O8 treatments respectively). Almond husk was used as an energy dilutor in the high-fat diets. Apparent absorption of total fatty acids was high in all treatments averaging 88% and was higher with high fat dietary inclusion level. alpha-Tocopheryl acetate hydrolysis and apparent absorption of alpha-tocopherol were similar in both ages and were not affected by fat inclusion level, except for a reduction of the absorption in the low-fat diet (O2) in the E100 treatment at 20 d of age. Despite this lack of differences in hydrolysis and absorption, higher-fat PUFA diets induced lower concentrations of free alpha-tocopherol in the excreta, at high alpha-tocopherol doses, suggesting an increase in the destruction of alpha-tocopherol by lipid oxidation in the gastrointestinal tract. Similarly, total and hepatic alpha-tocopherol deposition was lower in the birds fed high-PUFA diets in the E200- and E400-supplemented birds, possibly due to a destruction of vitamin E when protecting these PUFA from lipid peroxidation. alpha-Tocopherol concentration in liver and, to a lesser extent, in plasma was a useful indicator of the degree of response of this vitamin to different factors that can affect its bioavailability; however, in the present experiment, CV were too high to use liver and plasma concentrations as estimators of total body vitamin E.

Chemical composition and energy content of chickens in response to different levels of dietary polyunsaturated fatty acids

Abstract Two experiments were performed to study the effect of dietary polyunsaturated fatty acids (PUFA) on abdominal fat pad weight and chemical composition of broilers. In Experiment 1, different fat sources were blended in different ratios keeping added fat level constant (9%). In Experiment 2, PUFA gradient was obtained by increasing the level of inclusion (2, 4, 6 and 8%) of PUFA-rich oil. The treatments had 15, 34, 45 and 61 and 28, 38, 48 and 59 g PUFA/kg diet, respectively. Apparent metabolizable energy intake was similar in both experiments, except for the more saturated diet in Experiment 1 (15 g PUFA/kg), where it was lower. In Experiment 1, abdominal fat pad weight, total body fat and body energy were lower in the animals on the high PUFA diets (p < 0.05) compared to the animals on the saturated-rich ones, meanwhile in Experiment 2 there were no differences on chemical and energy composition by increasing added PUFA-rich oil inclusion level. In conclusion, PUFA-rich chicken diets, compared to saturated-rich ones, cause a lower body fat deposition, but not compared to low-PUFA low-fat diets.

Feeder Use Patterns in Group-Housed Pregnant Sows Fed With an Unprotected Electronic Sow Feeder (Fitmix)

Previous studies on feeder use in group-housed pregnant sows focused on dynamic groups and protected electronic sow feeders (ESF). This study observed 60 pregnant sows, 1st to 8th parity—housed from Day 29 of pregnancy to 1 week before parturition in stable groups of 20 animals, 1 Fitmix feeder per group. Data from 25 nonconsecutive 24-hr feeding cycles showed sows making several visits to the feeder. Literature on conventional ESF indicated shorter daily feeder occupation. Daily feeder occupation per sow decreased over time (p < .001). The study observed maximum feeder activity in the hours following the start of each feeding cycle. During the experiment, there was a relatively stable, quickly established, and maintained feeder order (W > 0.80, p < .001). This highly correlated with dominance rank (r s = 0.80, p < .001). High-ranking sows fed earlier and made as many—but longer—visits as low-ranking sows; thus, they occupied the feeder more time every day (p < .01). Although optimization of the feeder efficiency may take several weeks, Fitmix seems an efficient feeding system for medium-size, stable groups of sows.

How many muscle samples are required to obtain reliable estimations of muscle fibre characteristics from pig longissimus muscle

In order to investigate the reliability of muscle fibre trait estimations of pig longissimus muscle and to derive the minimum number of samples required per muscle cross-section and animal, intraclass correlation coefficients (ICC, ϑˆ) were obtained by one-way analysis of variance. From each of 23 market weight pigs five samples, evenly distributed over the muscle cross-sectional area at the 12th/13th rib level, were taken and analyzed for various muscle fibre traits. The number of samples required per muscle cross-section was found to be different between selected fibre traits, ranging from a minimum of three (for number of muscle fibres) to a maximum of five or more (for mean fibre area, fibre type composition and relative area occupied by each fibre type). These findings should be taken as a recommendation, but their usefulness will depend upon the goal and conditions of future experiments.

Prediction of digestible protein content of dry extruded dog foods: comparison of methods

The aim of this study was to check the accuracy of laboratory methods to predict the apparent protein digestibility (CPd, %) and digestible protein content (DP, g/kgDM) of dog foods, avoiding the use of experimental animals in digestion trials. Twenty-eight commercial dry extruded dog foods were tested by three different methodologies: an adaptation of the in vitro incubation method described by Hervera et al. (J Anim Physiol Anim Nutr 2007, 91: 205) for estimation of digestible energy of commercial dog foods, a modification of the pH drop methodology proposed by Hsu et al. (J Food Sci 1977, 42: 1269) for protein evaluation of human foods and the Near Infra Red Spectroscopy (NIRS) technology. All the methods assessed revealed very good, similar accuracy in the prediction of DP content either using the in vitro method (r = 0.99; RSD = 6.76; CV = 2.31%), the pH drop method (r = 0.99; RSD = 6.94; CV = 3.02%) or the NIRS (R2 = 0.96; SECV = 10.50) method, although the in vitro digestion method showed the highest accuracy approach of in vivo crude protein apparent digestibility: CPd in vitro (r = 0.81; RSD = 2.01; CV = 2.41%); CPd pH-drop (r = 0.78; RSD = 2.48; CV = 2.98%) and NIRS (r(2)cv = 0.53; SECV = 2.37).

Aggressive behavior in two different group-housing systems for pregnant sows.

The study housed 120 pregnant sows from Day 29 of pregnancy to 1 week before parturition either in groups of 10 with trickle feeding (TRICKLE) or in groups of 20 with an unprotected electronic sow feeding (FITMIX). The study recorded aggressive interaction on 11 nonconsecutive days. Frequency of aggressive interactions was higher in FITMIX (p < .05); yet, intense physical contact was unusual in both systems (3% of the total interactions). Conflicts in FITMIX centered largely on the feeder (83% vs. 23% for FITMIX and TRICKLE, respectively [p < .05]); in TRICKLE, they occurred mainly in the resting area (13% vs. 48% for FITMIX and TRICKLE, respectively [p < .05]). Forty-six percent of the FITMIX sows (mostly gilts and subordinates) needed assistance to adapt to the feeding system. Eventually, 8.3% of the FITMIX sows failed to adapt and had to be removed. In conclusion, although aggressive interactions were mainly of low intensity, sequential feeding appeared to make FITMIX a more competitive feeding system.