Biomedical subjects

G G Mateos

Publications and source records attributed to G G Mateos.

14 recordsLinked to original sources

PubMed2004

Feeding regimen and enzyme supplementation to rye-based diets for broilers.

A trial was conducted to study the influence of feeding regimen [ad libitum, (AL) vs. feed restriction, (FR)] and supplementation of the diet with a combination of xylanase and beta-glucanase on physiological parameters and performance of broilers fed rye-based diets. There were 4 dietary treatments arranged factorially with 2 feeding regimens (0 vs. 30% FR from 4 to 14 d), 2 enzyme doses (0 vs. 500 ppm), and an additional corn control diet. Each treatment was replicated 9 times from 4 to 25 d (15 chicks caged together) and 6 times from 25 to 46 d. From 4 to 46 d of age, FR did not affect weight gain and improved feed conversion of broilers (P < 0.05). Also, FR reduced the incidence of leg disorders, digesta viscosity, and pasted vents (P < 0.01) and increased relative weight of gizzard (P < 0.001). Enzyme supplementation (ES) improved average daily gain and feed conversion at all ages (P < 0.01), and the beneficial effects were greater for AL than for FR birds (P < 0.10). Also, ES reduced digesta viscosity (P < 0.001), relative weights of gizzard (P < 0.05) and crop (P < 0.01), and jejunum length (P < 0.05). Compared with feeding corn, feeding rye AL with or without ES impaired growth and feed conversion from 4 to 46 d (P < 0.01) and increased incidence of leg disorders (P < 0.05), viscosity of jejunum content (P < 0.01), and jejunum length (P < 0.05). We concluded that rye in feed impaired broiler performance and increased digesta viscosity and incidence of leg disorders and that FR and ES reduced the magnitude of the problem. The beneficial effects of ES on bird performance were more evident when birds were fed AL.

Animal Feed↗

PubMed2004

The effects of gender and slaughter weight on the growth performance, carcass traits, and meat quality characteristics of heavy pigs.

Crossbred pigs (n = 192) from Piétrain x Large White sires mated to Landrace x Large White dams, with a mean BW of 75 +/- 1.3 kg, were used to investigate the effects of gender and slaughter weight (SW) on growth performance, carcass characteristics, and meat quality. Pens of pigs (eight pigs/pen) were assigned randomly to one of six treatments arranged in a 2 x 3 factorial design with two genders (barrows or gilts) and three SW (116, 124, or 133 kg). Each treatment was replicated four times. Over the entire trial, barrows had higher (P < 0.001) ADFI (as-fed basis) and ADG than gilts; however, gilts had higher (P < 0.05) gain-to-feed ratios (G:F) than barrows. Barrows had lower (P < 0.01) dressing percents than gilts and produced fatter (P < 0.001) carcasses that had lower trimmed shoulder (P < 0.10) and ham (P < 0.001) yields than gilts. There was a trend for the semimembranosus muscle (SM) from barrows to have a higher (P < 0.10) 45-min pH than that of gilts, but 24-h pH was 0.11 pH unit higher (P < 0.01) in the SM of barrows than gilts. Gender had no (P > 0.10) effect on the moisture and lipid content of the longissimus muscle (LM), nor did gender affect (P > 0.10) LM color, myoglobin content, or thaw loss percentage. However, the LM from barrows had lower (P < 0.05) cooking loss percentages and tended to have lower (P < 0.10) shear force values than the LM from gilts. Pigs slaughtered at 116 kg had higher (P < 0.05) ADG than pigs slaughtered at 124 and 133 kg. Daily feed intake (as-fed basis) was not (P > 0.10) different among SW; however, pigs slaughtered at 116 and 124 kg had higher (P < 0.001) G:F than those slaughtered at 133 kg. Dressing percent, backfat depth, carcass length, and ham and shoulder weights increased (P < 0.001) as SW increased from 116 to 133 kg. The initial (45-min) pH of the SM from pigs slaughtered at 133 kg was higher (P < 0.05) than from pigs slaughtered at 116 or 124 kg; however, 24-h pH was not (P > 0.10) affected by SW. The LM from pigs slaughtered at 133 kg was darker (lower L* values; P < 0.001), redder (higher a* value; P < 0.01), and had more (P < 0.001) myoglobin than the LM of pigs slaughtered at 116 and 124 kg. Barrows and gilts of this particular crossbreed can be used to produce acceptable quality fresh pork when slaughtered at 116 kg; however, increasing SW to 124 kg, or more, decreased live pig performance and carcass leanness without any additional benefits to pork quality attributes.

Animals↗

PubMed2003

Effect of enzyme addition to wheat-, barley- and rye-based diets on nutrient digestibility and performance of laying hens.

1. Laying hen performance, egg quality, intestinal viscosity and nutrient apparent digestibility were evaluated with respect to the main cereal used in the diet and dosage rate of a fungal beta-glucanase/xylanase enzyme complex. 2. Twelve diets were arranged factorially, with three soluble fibre cereals (SFC); 500 g/kg of wheat or barley or 350 g/kg of rye, and 4 enzyme concentrations (0, 250, 1250 and 2500 mg/kg). An additional control diet based on maize was also included. 3. The use of SFC in the diet instead of maize did not affect egg production or food efficiency, but hens fed on SFC diets exhibited a higher incidence of dirty eggs than hens fed on the maize diet (8-6 vs 4.6%; P<0.01). 4. Laying hens fed on enzyme-supplemented diets produced more eggs (2.1%; P<0.05) and had better food efficiency per dozen eggs (2.5%; P<005) than hens fed on non-supplemented diets. An excess of enzymes in the diet (10 times the recommended dose) did not produce any deleterious effect on laying hen productivity. 5. Enzyme supplementation (ES) reduced intestinal viscosity (P<0.001) and the incidence of dirty eggs (P<0.01). The reduction in viscosity was more pronounced in barley than in wheat or rye diets (P<0.05). 6. Apparent nutrient digestibility in SFC diets was higher with ES, including dry matter (3.1%; P=0.08), fat (4.4%; P<0.001), non-starch polysaccharides (83.3%; P<0.01) and AMEn (2.5%, P<0.01). 7. It is concluded that substitution of maize by SFC is facilitated by ES, especially with respect to egg production, food conversion efficiency and egg shell cleanliness. An excess of enzymes did not produce any deleterious effect on nutrient digestibility or performance of laying hens.

Animal Feed↗

PubMed2003

Influence of enzymes on performance and digestive parameters of broilers fed rye-based diets.

An experiment was conducted to study the influence of enzyme supplementation (ES) to rye-based diets on rate of food passage through the digestive tract, viscosity of jejunum content, volatile fatty acid concentration in ceca, and performance of broilers. There were seven treatments; six diets arranged factorially with three varieties of rye (Petkus, Prima, and Saratov V) and two levels of ES (0 or 500 ppm of an enzyme complex containing 858 IU of beta-glucanase and 864 IU of xylanase/g) and an additional control diet based on corn. Each treatment was replicated seven times (12 chicks caged together), and the trial lasted 25 d. Rye feeding increased intestinal viscosity and impaired bird performance at 25 d (P < 0.001). Among rye diets the greatest feed intake and weight gain were obtained with Petkus variety, which also produced the lowest intestinal viscosity. Enzyme addition reduced the time needed to recover 1% (0.78 vs. 0.98 h; P < 0.05) and 50% (4.2 vs. 6.5 h; P < 0.01) of the marker in feces and reduced the mean retention time of marker in the gastrointestinal tract (17.1 vs. 18.8 h; P < 0.05). Also, ES reduced intestinal viscosity (P < 0.001) and improved feed intake, daily gain, and feed conversion of birds from 4 to 25 d (P < 0.01) but did not modify volatile fatty acid concentration in ceca. We concluded that ES added to rye diets decreased intestinal viscosity and accelerated digestive transit, improving productive performance of broilers.

Animal Nutritional Physiological Phenomena↗

PubMed2003

Alpha-amylase supplementation of broiler diets based on corn.

A 42-d trial was conducted to study the influence of exogenous alpha-amylase on digestive and performance traits in broilers fed a corn-soybean meal diet. There were two treatments (control and alpha-amylase supplemented diet) and six replicates (14 Cobb male chicks caged together) per treatment. At 7 d of age, alpha-amylase supplementation improved daily gain by 9.4% (P < or = 0.05) and feed conversion by 4.2% (P < or = 0.01). At the end of the trial, birds fed the alpha-amylase-supplemented diet ate more and grew faster (P < or = 0.05) and hadbetter feed conversion (P < or = 0.10) than broilers fed the control diet. Also, alpha-amylase supplementation improved apparent fecal digestibility of organic matter and starch (P < or = 0.01) and AMEn of the diet (P < or = 0.001). However, no effects were detected for CP or fat digestibility. Nutrient digestibility and AMEn of the diet increased with age (P < or = 0.001); however, no interactions of alpha-amylase x age were observed for any trait. Coefficients of apparent ileal and fecal digestibility of starch at 28 d of age were similar, which indicated that most of the undigested starch was not fermented in the hindgut of the chick. alpha-Amylase supplementation reduced relative pancreas weight (P < or = 0.001) but did not affect the weight of the remaining organs. Age consistently reduced intestinal viscosity and relative weights of all the organs (P < or = 0.001). The data indicated that alpha-amylase supplementation of a corn-soybean meal diet improved digestibility of nutrients and performance of broilers.

Aging↗

PubMed2003

Heat processing of barley and enzyme supplementation of diets for broilers.

The influence of heat processing (HP) of barley and enzyme supplementation (ES) of the diet on digestive and performance traits of broilers to 21 d was studied. There were four treatments arranged factorially with two barley-processing treatments (raw or heated), two levels of ES (0 or 500 ppm), and five replicates per treatment. Chicks fed HP barley grew faster than broilers fed raw barley until 8 d of age, but the effect disappeared thereafter. In general, ES improved broiler performance at all ages. Intestinal viscosity was increased by HP of barley (P < or = 0.05) and reduced by ES (P < or = 0.001), and the decrease in viscosity caused by ES was greater for HP than for raw barley diets (HP x ES; P < or = 0.05). Heat processing of barley and ES of the diet improved apparent retention of nutrients (P < or = 0.001). Age affected apparent retention of nutrients differently. For starch and neutral detergent fiber, retention increased linearly with age (P < or = 0.01), but for the remaining nutrients the retention decreased from d 4 to 8 and then increased until d 21 (P < or = 0.001). Also, the beneficial effects of HP on retention of nutrients were more pronounced at younger ages (HP x age; P < or = 0.05). Both HP (P < or = 0.001) and ES (P < or = 0.01) increased liver weight, and enzymes reduced the weights of pancreas (P < or = 0.05) and small intestine (P < or = 0.001). Villus height was improved by HP (P < or = 0.001) and ES (P < or = 0.01), but villus surface area was only improved by enzymes (P < or = 0.01). It was concluded that broiler performance is improved by HP of barley at early ages and by ES of the diet throughout the trial. Also, HP and ES increased apparent retention of nutrients, AMEn of the diet, and villus height.

Animal Nutritional Physiological Phenomena↗

PubMed2002

Effect of vitamin E and A supplementation on egg yolk alpha-tocopherol concentration.

The objective of this study was to asses the effect of dietary dl-alpha-tocopheryl acetate (alpha-TAC) and vitamin A supplementation on egg yolk alpha-tocopherol (alpha-T) concentration. A total of 96 ISA brown hens (a brown-egg laying hen), 32 wk of age, was used. Eight concentrations of alpha-TAC (0, 20, 40, 80, 160, 320, 640, and 1,280 IU/kg diet) were included in a corn-soybean meal-based diet containing 4,000 IU of vitamin A/kg diet. Production parameters were not affected by dietary treatment. Interhen variation in yolk alpha-T concentration increased at higher dietary intakes. Logarithmic transformation stabilized variance and showed the existence of a linear relationship between dietary alpha-TAC supplementation level and alpha-T egg yolk concentration (P < 0.001). As the dietary concentration of alpha-TAC rose, efficiency of uptake of alpha-T from feed to yolk decreased linearly (P < 0.001). A parallel experiment was carried out in which four additional groups of hens were fed diets containing four levels of dietary alpha-TAC (0, 40, 160, and 640 IU/kg) and 40,000 IU vitamin A/kg diet. A significantly lower egg yolk alpha-T concentration was found in hens fed diets including the highest level of vitamin A supplementation (P < 0.001). No interaction of dietary alpha-TAC and vitamin A concentrations was observed on egg yolk alpha-T concentration. No effect of dietary treatment was observed on yolk oxidation and other egg quality characteristics.

Animals↗

PubMed1999

Influence of dietary energy, supplemental fat and linoleic acid concentration on performance of laying hens at two ages.

1. The aim of this study was to investigate the influence of metabolisable energy (ME), supplemental fat (SFAT) and linoleic acid (LIN) content of the diet on the productive performance and weight of eggs and egg components of Isabrown hens of 22 or 74 weeks of age. 2. Six diets were formulated to contain the following concentrations of ME (MJ/kg), SFAT (g/kg) and LIN (g/kg), respectively: A) 11.8, 0 and 11.5; B) 11.8, 40 and 11.5; C) 11.8, 40 and 16.5; D) 11.2, 40 and 16.5; E) 11.2, 40 and 11.5; and F) 11.2, 0 and 11.5. Data were collected for 28 d and analysed using linear contrasts to test the effect of SFAT, LIN, ME and their interactions. 3. When the LIN content of the diets was maintained constant at 11.5 g/kg, an increase in the SFAT from 0 to 40 g/kg increased egg weight (63.8 vs 64.5 g; P<0.05), food intake (119 vs 124 g; P<0.01) and energy intake (1.36 vs. 1.42 MJ/d; P<0.01) and body weight change of the hens (-85 vs. 27 g; P<0.001). Supplemental fat also increased yolk (15.8 vs. 16.3 g; P<0.001) and albumen weight (40.8 vs. 42.3 g; P<0.01) but yolk to albumen ratio was not modified. 4. Egg and albumen weights were improved by SFAT in early but not in late producing hens. As a result, yolk to albumen ratio decreased in the younger hens, from 0.371 to 0.357, but increased in the older hens, from 0.408 to 0.415; P<0.01) with fat addition. 5. An increase in the LIN content of the diets from 11.5 to 16.5 g/kg did not modify any of the traits studied. 6. It was concluded that the LIN requirement of the hens for maximal productivity and weight of eggs is 11.5 g/kg or less. Supplemental fat increased the weight of eggs and albumen in the younger but not in older hens and the beneficial effect was independent of its LIN content.

Animal Feed↗

PubMed1999

Laying hen productivity as affected by energy, supplemental fat, and linoleic acid concentration of the diet.

A trial using 720 Isabrown hens was conducted to determine the influence of energy (AMEn), supplemental fat (SFAT), and linolenic acid (LIN) concentration of the diet on performance and weight of eggs and egg components throughout the laying cycle (22 to 65 wk of age). There were six treatments whose calculated AMEn, SFAT, and LIN content were, respectively: 1) 2,810 kcal/kg, 0%, 1.15%; 2) 2,810 kcal/kg, 4%, 1.15%; 3) 2,810 kcal/kg, 4%, 1.65%; 4) 2,680 kcal/kg, 0%, 1.15%; 5) 2,680 kcal/kg, 4%, 1.15%; and 6) 2,680 kcal/kg, 4%, and 1.65%. All diets were formulated to have the same crude protein, lysine, TSAA, calcium, and nonphytin phosphorus levels per kilocalorie of AMEn. The data were analyzed with SFAT constant (4%) and AMEn, and LIN variables (Diets 2, 3, 5, and 6) and with LIN constant (1.15%) and AMEn and SFAT variables (Diets 1, 2, 4, and 5). When LIN was maintained at a constant of 1.15%, an increase in the AMEn of the diets from 2,680 to 2,810 kcal/kg decreased feed intake by 4% (P < 0.001). Increasing AMEn also improved feed conversion per dozen eggs and per kilogram of eggs by 4.9 and 4.7% (P < 0.05), respectively, and increased BW gain by 55.7% (P < 0.05). Egg production rate, egg weight, egg mass output, and energy intake were not modified by treatments. An increase in SFAT within both energy levels from 0 to 4% improved all of the traits studied except feed conversion. Supplemental fat increased both yolk and albumen weight, but the effect was more pronounced on the latter. When SFAT was maintained constant at 4%, an increase in AMEn of the diets decreased feed intake and improved feed conversion per dozen and per kilogram of eggs by 5.7, 5.5, and 5.2%, respectively (P < 0.001). An increase in LIN content from 1.15 to 1.65% did not modify any of the parameters studied. The results indicate that SFAT consistently improves productivity of hens and egg weight and that the LIN requirement for maximal productivity is 1.15% or less. The beneficial effects of adding SFAT to diets containing more than 1.15% LIN are due to the fat itself rather than to an increase in LIN or AMEn of the diet.

Aging↗

PubMed1995

Effect of substitution of starch for fiber and fat in isoenergetic diets on nutrient digestibility and reproductive performance of rabbits.

The optimal level of starch in diets for rabbit does was investigated. Five isoenergetic and isoproteic diets containing 26.6, 24.6, 19.0, 16.8, or 13.0% starch and 31.2, 33.4, 36.0, or 41.2% NDF, respectively (DM basis), were made by substitution of starch for NDF and fat. The effect of diet on nutrient digestibility was determined in fattening and nonlactating and lactating adult does using a total of 105 rabbits. Increasing dietary starch content linearly increased (P < .001) DM, GE, CP (P = .07), and starch digestibilities but decreased (P < .001) NDF digestibility. Nutrient digestibility was higher (P < .05), except for CP, in adult does than in fattening rabbits. Dry matter and GE digestibilities were higher (P = .08) for nonlactating than for lactating does. A lactation trial using 440 rabbit does was conducted over a 6-mo experimental period. Milk production and milk composition were measured in 70 lactations. A decrease in dietary starch content did not improve pup mortality before weaning but impaired (linear, P < .001) dry feed intake and pup growth from 21 d until weaning. Diet did not influence does' feed intake, milk DM, ether extract, and CP contents or prolificacy. However, diet had quadratic effects on milk production (P = .15), milk lactose content (P = .07), parturition interval (P = .02), and feed conversion efficiency (P = .02), expressed both per weight or number of pups weaned. Optimal values were reached for dietary starch and NDF contents at approximately 20 and 35.5% (DM basis), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1982

Rate of food passage (transit time) as influenced by level of supplemental fat.

An experiment involving 35 White Leghorn hens was conducted to study the influence of graded levels of supplemental yellow grease on rate of food passage (transit time). Seven experimental diets (0, 5, 10, 15, 20, 25, and 30% supplemental fat) were formulated. Transit time was determined by utilizing either Cr2O3 or 144Ce as indicators. First appearance of the markers in the excreta and percentages of the markers ingested that were recovered in excreta 10 hr after feeding were criteria used to determine transit time. There was a significant (P less than .01) linear effect of fat on transit time of Cr2O3 whereby the time required for the marker to appear in the excreta increased with increments of supplemental fat. Average first appearance time of Cr2O3 was 193, 219, 214, 227, 251, 250, and 270 min for the diets containing 0, 5, 10, 15, 20, 25, and 30% supplemental fat, respectively. Transit time of 144Ce also was increased slightly (P less than .10) by fat supplementation. Transit time, measured as percentage of marker recovered in excreta 10 hr after feeding, was faster for the control than for the fat-supplemented diets, although the linear effects of fat were not statistically significant (P greater than .10). The results show that supplemental fat increased transit time of ingesta in chickens. This observation may be helpful in understanding the nature of the extrametabolic effect of fat in poultry diets. By increasing transit time, supplemental fats may improve digestibility of other dietary constituents and thereby increase the utilization of dietary energy.

Animals↗

PubMed1980

Influence of graded levels of fat on utilization of pure carbohydrate by the laying hen.

An experiment involving 140 SCWL laying hens was conducted to investigate the influence of graded levels of supplemental fat on the nitrogen-corrected metabolizable energy (ME) of diets containing different carbohydrates. Twenty-four diets with the same ME: protein ratio were arranged in a 4 X 6 factorial composed of four levels of yellow grease (0, 3, 6 and 9%) and six carbohydrate sources (sucrose, starch, maltose, glucose, fructose, and glucose + fructose). Four additional diets in which the specific carbohydrate was not included, were formulated to facilitate the determination of the MEn of the carbohydrates. The ME of each carbohydrate increased with each increment of supplemental fat. When yellow grease constituted 0 or 9% of the diet, the respective ME values of the carbohydrates (kcal/kg), expressed in a relative index form with the ME of sucrose in diets without added fat set equal to 100, were 100 and 110 for sucrose, 96 and 103 for starch, 93 and 100 for maltose, 92 and 101 for glucose, 90 and 98 for fructose and 89 and 98 for the glucose + fructose mixture. The data indicate that supplemental fat enhanced the utilization of energy from nonlipid dietary constituents. The mechanism by which fat exerts this influence on utilization of dietary energy is not known, but the possible relationship between decreased rat of food passage resulting from supplemental fat and energy utilization is discussed.

Animals↗

PubMed1980

True and apparent metabolizable energy value of fat for laying hens: influence of level of use.

White Leghorn hens in egg production were fed rations that contained 0, 3, 6, 9, 12, or 15% yellow grease. True metabolizable energy (TME) and nitrogen-corrected apparent metabolizable energy (AMEn) values of the rations were determined, and these data were used to estimate the TME and AMEn of yellow grease. An inverse relationship was observed between the level of yellow grease supplementation and the TME and AMEn values of this fat source. The TME and AMEn of yellow grease were 11,567 and 9,367 kcal/kg, respectively, when the supplemental level was 3%. Corresponding values when yellow grease constituted 15% of the ration were 8,907 and 8,653 kcal/kg, respectively. Variation in fatty acid composition of total dietary fat and associated changes in the TME and AMEn of yellow grease are discussed.

Animals↗

PubMed1980

Influence of carbohydrate and supplemental fat source on the metabolizable energy of the diet.

An experiment involving 60 Single Comb White Leghorn laying hens was conducted to measure the influence of the carbohydrate source and supplemental fat on nitrogen-corrected metabolizable energy(MEn) of the diet. Twelve diets with the same calculated metabolizable energy (ME) and protein levels were arranged in a 2 X 6 factorial composed of two different yellow grease to soy oil ratios (6%:0% and 4%:2% of the diet) and 6 corn starch to sucrose ratios (from 49%:0% to 0%:49%). The diets were assayed for MEn content by using the total feces collection method. There was a positive linear relationship between sucrose level and MEn of the diet. When sucrose replaced corn starch, the MEn of the diets increased more than expectd, and these increments were statistically significant (P < .01). The diets containing a mixture of yellow grease and soy oil had significantly higher MEn values than those in which supplemental fat was supplied exclusively as yellow grease (P < .05). A comparison of the "calculated" regression equation describing the expected dietary ME with changing sucrose and soy oil levels, Y = 3110 + 1.03 (% sucrose) + 9 (% soy oil), and the regression equation determined experimentally, Y = 3177 + 3.25 (% sucrose) + 18 (% soy oil), illustrates the relatively large increases in dietary ME caused by sucrose and soy oil. These effects of sucrose and soy oil were independent. These data support the concept that the addition of a relatively unsaturated fat (soy oil) to a saturated fat (yellow grease) enhances dietary MEn. Also, the data indicate that the presence of supplemental fat in the diet increases the utilization of energy from sucrose. Thus, the "extra-caloric" effect of fats on MEn may be the culmination of a favorable interaction between supplemental fats and fats inherent in other diet components, and a beneficial influence of supplemental fats on energy utilization from certain nonlipid dietary constituents.

Animals↗