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PubMed2001

Early weaning and postweaning nutritional management affect feedlot performance of angus x simmental heifers and the relationship of 12th rib fat and marbling score to feed efficiency.

Early-weaned Angus x Simmental heifers were used to evaluate the effects of postweaning nutritional management on feedlot performance, carcass merit, and the relationship of intramuscular and subcutaneous fat deposition to the feed efficiency among heifers fed for a high-quality market. Sixteen heifers were weaned at 73+/-5.5 d of age and grazed on endophyte-infected tall fescue for 18 mo before entering the feedlot (early-weaned-P). Eighty heifers from the following year's calf crop were weaned at 71+/-5.5 d of age and allowed either ad libitum access to a 25% concentrate diet (early-weaned-25C) or limit-fed a 90% concentrate diet (early-weaned-90C) to achieve a similar ADG. Following a 119-d growing period, 16 early-weaned-90C and 16 early-weaned-25C calves were paired based on BW and growth rate and individually fed during the finishing period along with the early-weaned-P heifers. Ultrasound measurements of s.c. and i.m. fat were recorded at approximately 60-d intervals throughout the finishing period. Feed efficiency was regressed against s.c. and i.m. fat, and i.m. fat was regressed on s.c. fat. Despite a similar ADG, early-weaned-90C calves gained more efficiently (P < or = 0.05) in the feedlot than early-weaned-25C calves. Heifers finished as yearlings tended (P < or = 0.10) to gain faster but gained less efficiently (P < or = 0.01) than early-weaned-90C heifers finished as calves. The rate of s.c. and i.m. fat deposition was similar between early-weaned-90C and early-weaned-25C heifer calves. The calves were grouped together for comparison to yearlings. Feed efficiency decreased quadratically (P < or = 0.01) as s.c. fat cover increased. The rate at which feed efficiency decreased relative to increasing s.c. fat cover was similar regardless of age at feedlot entry. However, heifers finished as calves gained more efficiently (P < or = 0.01) than yearlings at any given fat thickness. Feed efficiency decreased linearly (P < or = 0.01) as i.m. fat increased among heifers finished as calves. Additionally, heifers finished as calves deposited i.m. fat at a faster rate relative to s.c. fat (P < or = 0.01) than yearlings. These data suggest that heifers finished as calves produce high-quality carcasses with less s.c. fat cover while gaining more efficiently than heifers finished as yearlings.

Adipose Tissue↗

PubMed1992

No persistent effect of preweaning nutrition on postweaning food intake, feeding efficiency, or body energy stores in Long-Evans rats.

The purpose of this study was to determine the relative importance of pre- and postweaning nutrition on body mass, body fat, and feeding efficiency in Long-Evans rats up to a period of 18 weeks following weaning. Female rats were bred and pups were redistributed to form large (14-19 pups), normal (11-13 pups) and small (4 pups) litter groups. Weaned rats were housed as pairs (40 pairs) or singletons (n = 16) and fed either a mixed-fat diet (36.6% fat) or a standard chow diet (13.5% fat). Food intake, body mass, and feeding efficiency were measured at 4, 8, 12, and 18 weeks postweaning. Total body fat and depot fat pad mass were also measured at 18 weeks postweaning. At weaning, pups from small litters were fatter (p less than 0.001), and had a greater mass (p less than 0.03) than pups from large litters. There were no persistent effects of preweaning litter size after covarying for preweaning mass on body mass, and postweaning growth, food intake, feeding efficiency, or body fat accretion. Male rats ingesting the mixed-fat diet had a greater body mass (p less than 0.05), greater body fat accretion (p less than 0.008) and a higher feeding efficiency (p less than 0.001) than their chow-fed counterparts, despite an overall lower energy intake (p less than 0.05). Female rats ingesting the mixed-fat diet had a lower food energy intake (p less than 0.005) and a greater feeding efficiency (p less than 0.001) than chow-fed rats during the early postweaning period, only. Thus, postweaning nutrition may play a more important role in postweaning adult mass and depot fat in freely eating rats than early nutritional experiences.

Adipose Tissue↗

PubMed1993

Exercise training alters feed efficiency and body composition in iron deficient rats.

Studies of body composition and feed efficiency were conducted on 80 male Sprague-Dawley rats to determine how exercise training alters growth and development in iron deficient animals. Animals were assigned to iron deficient (ID) or control (CN) diets (AIN-76, w/o cellulose), and sedentary (SD) or exercised groups [EX, treadmill running, 4 d.wk-1, 90 min.d-1, 65% maximal oxygen consumption (VO2max), maintained for 6 or 12 wk. The ID diet caused a sustained moderate iron deficiency (Hb 7.2 +/- 0.2 g.dl-1). Iron deficient animals failed to increase maximal oxygen consumption despite the rigorous training program, through training resulted in 25% or 35% higher VO2max in 6- or 12-wk CN rats. At 6 wk, IDEX animals had significantly (33%) lower growth rates than did IDSD animals, which in turn were 22% less than CNs. Overall, exercise did not alter relative amounts of protein in the carcass (% total mass); however, a significant interaction between diet and treatment duration was evident in IDEX animals at 12 wk, who had lower % protein than CNEX-12 or IDSD-6 rats. Training decreased fat 11% in CN at 6 wk but not 12 wk, and 20% in IDs at 12 wk but not 6 wk. Feed efficiency and energy intake were 28% and 12% lower in IDEX animals than CNEX at 6 wk. Training increased caloric intake in CNEX animals but not IDEX animals at 6 and 12 wk. Thus, exercise training exacerbates the poor growth associated with ID through alterations in both food intake and feed efficiency in early phases of training, but adaptation is apparent.

Animals↗

PubMed1986

Heterotic and maternal effects in L and S growth strain rats: II. Body weight gains, feed consumption and feed efficiency.

A diallel cross between two strains of rats from the same genetic source, that vary greatly in body size, was made in order to evaluate the differences in individual gain, feed consumption and feed efficiency (gain/feed) from 4 to 15 wk of age. Significant paternal, maternal and sex effects were evident for all weekly gains and feed consumption. These effects were not significant for feed efficiency. Offspring of Large Line (L) rats grew faster and consumed more feed than offspring of Small line (S) rats. Cross-bred mating types (LS and SL) were significantly different as SL rats were faster growing with greater feed consumption than LS rats indicating a significant maternal effect of L female. Heterosis for growth rate was positive and feed consumption negative; however, neither was significant. No significant line of sire, line of dam or heterosis effects on feed efficiency were seen. Analysis of this mating design indicates that increased gain was due to increased feed consumption rather than increased feed efficiency; and, any heterotic effects in this cross between extremes in body size, if present, were masked by maternal effects.

Alleles↗

PubMed1984

Effects of diet and antimicrobials on growth, feed efficiency, intestinal Clostridium perfringens, and ileal weight of broiler chicks.

Five experiments were conducted to evaluate the effects of diet and antimicrobials on weight gain, feed efficiency, ileal weight, and Clostridium perfringens in the ileum of broiler chicks. In the first experiment, glucose, sucrose, and fructose were added to a semipurified diet and the results were compared with those from a practical corn and soybean meal diet. All of the diets were fed with and without bacitracin at a level of 55 ppm. Fructose resulted in the greatest depression in weight gain, followed by sucrose. Bacitracin significantly improved weight gain and feed efficiency of chicks fed the fructose, sucrose, and practical diets. Highly significant inverse correlations were obtained between ileal weight and weight gain and the number of C. perfringens in the ileum and weight gain. In other experiments bacitracin, penicillin, chlortetracycline, oxytetracycline, erythromycin, tylosin, virginiamycin, lincomycin, bambermycins, and carbadox, all at a level of 55 ppm, improved weight gain and feed efficiency and significantly reduced the weight of the ileum and the number of C. perfringens in the ileum of chicks fed the practical diet. The antibacterial agents 3-nitro-4-hydroxy-phenylarsonic acid, arsanilic acid, furazolidone, and sulfathiazole had little to no effect on the 4 parameters evaluated. Virginiamycin and lincomycin at 16.5 and 4.4 ppm, respectively, were shown to be effective. In vitro activities of the antimicrobials against C. perfringens did not directly relate to in vivo activities and the effects on growth and feed efficiency. The results of these experiments support the concept of antimicrobials as growth permittants and provide further evidence for C. perfringens as a causative bacteria for growth depression.

Animal Feed↗

PubMed1999

The effects of accelerated growth rates and estrogen implants in prepubertal Holstein heifers on growth, feed efficiency, and blood parameters.

Sixty-eight Holstein heifers were used to determine the effects of accelerated growth rates by increased nutrient intake and estrogen implants on feed efficiency, structural growth, and blood parameters in heifers between 19 and 39 wk of age. At the beginning of the treatment period, the heifers were assigned to one of four treatment groups by using a randomized complete block design in a 2 x 2 factorial arrangement. The treatments were standard growth rate (700 g/d), accelerated growth rate (1000 g/d), standard growth rate with an estradiol implant, and accelerated growth rate with an estradiol implant. All heifers received the same diet, but dry matter intake was adjusted weekly to achieve the target rate of gain. Accelerating heifer growth rates from 705 to 1007 g/d improved feed efficiency 5.1%, increased the rate of withers height, heart girth, and hip width growth 12, 27, and 27%, respectively, and body condition scores 0.25 points. Estradiol implants improved feed efficiency 2.4% and decreased the rate of withers height 6% and heart girth growth 3.5%. Increased nutrient intake and average daily gain depressed mean plasma growth hormone and urea nitrogen content 17 and 7%, respectively, while elevating insulin-like growth factor-1 levels by 10%. Estradiol implants increased mean plasma growth hormone content by 29% and insulin-like growth factor-1 levels by 17%, but decreased urea nitrogen content by 11%. Feeding prepubertal heifers for accelerated growth rates increased structural growth with a small increase in body condition, whereas estradiol implants improved feed efficiency and decreased the growth rate of withers height and heart girth without affecting the rate of hip width growth.

Animal Nutritional Physiological Phenomena↗

PubMed2002

Effects of administration of antimicrobials in feed on growth rate and feed efficiency of pigs in multisite production systems.

OBJECTIVE: To evaluate effect of various regimens for administration of antimicrobials in feed on growth rate and feed efficiency (feed/gain) of pigs in multisite production systems. DESIGN: Controlled trial. ANIMALS: 24,099 growing pigs in 3 multisite production systems. PROCEDURE: 10 trials involving various regimens for administration of antimicrobials in feed were evaluated. Trial 1 compared effects of 2 antimicrobial regimens on finishing pig performance. Trials 2 through 10 compared growth rate and feed efficiency of nursery and finishing pigs given antimicrobials in feed with values for control pigs not given antimicrobials. RESULTS: In trial 1, no significant differences were observed between the 2 antimicrobial regimens. In the remaining trials, growth rate of nursery pigs fed antimicrobials was significantly improved, compared with growth rate of control pigs. However, growth rate of finishing pigs and feed efficiency of nursery and finishing pigs were not significantly improved by adding antimicrobials to the feed. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that use of antimicrobials in the feed to promote growth should be limited to the nursery phase in multisite pig production systems. Use of antimicrobials in the feed of finishing pigs should be limited to therapeutic applications in which a diagnosis of bacterial infection susceptible to the antimicrobial to be used has been confirmed.

Age Factors↗

PubMed1986

Influence of hog lice, Haematopinus suis, on blood components, behavior, weight gain and feed efficiency of pigs.

Blood components, behavior, weight gain and feed efficiency were studied in 40 weaner pigs infested with lice and 40 left uninfested (controls). Packed cell volumes and concentrations of hemoglobin, serum proteins, leukocytes, serum globulins, and serum albumins increased significantly in both groups. Eosinophil concentrations increased and neutrophil concentrations decreased in the infested group but not in the controls. There was a significant increase in erythrocyte concentrations in the control group while the infested group's erythrocyte concentrations decreased at the middle of the experiment. Blood of infested and uninfested pigs showed no significant differences from pre-infestation values in sedimentation rates and concentrations of fibrinogen, basophils, and monocytes. Control pigs spent more time at feeders and more time active while not at feeders. Nevertheless, average daily gains (ADG) and feed efficiencies (FE) of the two groups were not significantly different. When ADG and FE were grouped by severity of Haematopinus suis infestation, pigs with more H. suis had higher ADG and better FE than pigs with fewer or no lice. The results suggest that a decrease in activity by infested pigs allows them to save energy which is then available for growth.

Animals↗

PubMed2000

The response of altering the ratio of dietary protein to energy on growth, feed efficiency, and mammary development in rapidly growing prepubertal heifers.

This study was conducted to evaluate the effects of increasing the ratio of dietary protein to energy above National Research Council recommendations on average daily gain, feed efficiency, structural growth, and indirect measurements of mammary growth. Forty-five Holstein heifers were randomly assigned to either a low, medium, or high ratio of dietary crude protein (CP) to metabolizable energy of 46:1, 54:1, and 61:1 g/Mcal, respectively. The ratio of dietary protein to energy was altered by adjusting the concentration of CP with a similar amount of energy across all diets. Heifers were individually fed and began the treatment period at 200 kg of body weight and 28 wk of age. During the 3-wk adaptation period and 20-wk treatment period, all heifers were fed for a daily dry matter intake (DMI) of 2.45% of body weight. Body weight was monitored for two consecutive days each week and was used to adjust the dry matter offered on a weekly basis. The high versus low ratio of dietary protein to energy increased feed efficiency 6%, which resulted in larger heifers that were subsequently fed 3% more DMI over the course of the trial. The increased feed efficiency and DMI increased average daily gain by 9% for the high versus low ratio of dietary protein to energy. For the high versus low ratio of dietary protein to energy, hip width, hip height, wither height, and heart girth growth was increased 13, 16, 18, and 12%, respectively. The heifers fed the high ratio of dietary protein to energy had a lower rate of increased body condition score compared with the heifers fed the low ratio of dietary protein to energy. Teat length growth was used as an indirect measurement of mammary ductal development and was increased by 35 to 38% for heifers on the high versus low ratio of dietary protein to energy. Feeding dietary ratios of protein to energy above NRC recommendations improved feed efficiency and increased average daily gain, structural growth, and mammary development while decreasing body condition scores in heifers between 28 and 48 wk of age.

Animal Nutritional Physiological Phenomena↗

PubMed1998

Insulin-like growth factor (IGF)-I but not IGF-II promotes lean growth and feed efficiency in broiler chickens.

The efficacy of exogenous IGFs to stimulate growth and modulate protein and fat deposition was examined in a number of broiler chicken lines. From around 600 g body weight the chickens received a continuous infusion of vehicle (0.1 M acetic acid), human recombinant IGF-I or [Gly1]IGF-II at 300 microg/kg body weight per day, or a combined infusion of 150 microg/kg/day of each IGF for 2 weeks. Experiment 1 used commercial broiler female chickens and included measurements of nitrogen balance, Ntau-methylhistidine excretion and muscle protein synthesis rates. In Experiment 2 the same treatments were applied to three experimental lines of chickens selected for high food consumption (relatively fat), high food utilisation efficiency (relatively lean), or at random (control). IGF-I, but not IGF-II, significantly increased growth rate and food utilisation efficiency by around 10-15% in each experiment, an effect which was consistent across all genotypes. Nitrogen balance was significantly increased by IGF-I in Experiment 1 as was carcass nitrogen content in Experiment 2, indicating that the increased growth was in lean tissue. Carcass fat was consistently reduced in chickens receiving IGF-I and was related to the levels of circulating IGF-I (r2 = 0.30, P < 0.01) but not triiodothyronine. Protein synthesis rates were unaffected by treatment and could not account for increased growth rate. However, there was a significant reduction in Ntau-methylhistidine excretion indicating a reduced rate of muscle protein breakdown in IGF-I-treated chickens (1. 56%/day vs 2.05%/day for IGF-I-treated vs controls, P < 0.05). The efficiency of feed utilisation was inversely related to the rate of protein breakdown (r2 = 0.25, P < 0.01). In conclusion, these experiments are the first to report an enhancement of growth and food utilisation efficiency by broiler chickens receiving exogenous IGF-I. Our results show that IGF-I may be important in controlling the growth and efficiency of food utilisation of young chickens at least in part by modulating the rates of protein breakdown.

Animal Nutritional Physiological Phenomena↗

PubMed1984

Genetic and physiological aspects of growth, body composition and feed efficiency in mice: a review.

A review is presented of the genetic and physiological aspects of growth, body composition and feed efficiency in mice. The genetic parameters considered are: nature and extent of within and between-line genetic variation for body weight and growth rate; direct and correlated responses to selection for body weight, weight gain, feed intake and feed efficiency; direct genetic effects of the offspring (gO); maternal genetic effects (gM); heterosis in the offspring (hO); maternal heterosis (hM), and recombination effects in the offspring (rO). The physiological parameters considered are energy requirements for maintenance and growth. The role of thermoregulatory thermogenesis in relation to the partitioning of metabolizable energy between maintenance and growth requirements of large and small mice is emphasized. The relationship of feed efficiency with other traits is reviewed at length.

Animal Feed↗

PubMed2006

Feed efficiency of rainbow trout can be improved through selection: different genetic potential on alternative diets.

To assess the genetic potential for selection of increased feed efficiency in rainbow trout (Oncorhynchus mykiss), we estimated the heritabilities and correlations for BW, daily weight gain (DG), and daily feed intake (DFI). Body weight was recorded 5 times, and DG and DFI 3 times during a feeding trial lasting 22 mo. To test the hypothesis that phenotypic and genetic parameters were influenced by a nutritional environment, fish were fed either a modern normal protein diet (NP, 40 to 45% protein and 30 to 33% lipid) or an alternative high protein diet (HP, 50 to 56% protein, 20 to 24% lipid) in a split-family design. Results showed that there were no large differences in heritabilities between the diets. Average heritability for DFI over both diets and different fish ages was low (average h2 = 0.10), indicating that modest genetic changes in response to selection can be obtained. Average heritabilities for BW and DG over both diets and different fish ages were 0.28 and 0.33, respectively. The NP diet enabled fish to express a wide range of BW, as shown by the increased coefficients of phenotypic variation for BW. Fish fed the HP diet showed increased phenotypic variation for DFI in > 750-g fish. On the NP diet, genetic correlations of DFI with DG and BW were very strong for 750- to 2,000-g fish. In contrast, on the HP diet, the respective correlations were moderate to low, revealing more genetic potential to change growth and feed intake simultaneously in opposite directions. An analysis of the predicted selection responses showed that selection solely for high DG improved feed efficiency as a correlated genetic response. Simultaneous selection for high DG and reduced DFI, in turn, may increase genetic gain in feed efficiency by a factor of 1.2 compared with selection solely for DG. However, variation for growth and feed intake and the relationships between these traits were different in different nutritional environments, leading to divergent genetic responses on the alternative diets.

Animal Feed↗

PubMed2005

Genetic parameters of ascites-related traits in broilers: correlations with feed efficiency and carcase traits.

(1) Pulmonary hypertension syndrome followed by ascites is a metabolic disorder in broilers that occurs more often in fast-growing birds and at cool temperatures. (2) Knowledge of the genetic relationships among ascites-related traits and performance traits like carcase traits or feed efficiency traits is required to design breeding programmes that aim to improve the degree of resistance to ascites syndrome as well as production traits. The objective of this study was to estimate these genetic correlations. (3) Three different experiments were set up to measure ascites-related traits (4202 birds), feed efficiency traits (2166 birds) and carcase traits (2036 birds). The birds in different experiments originated from the same group of parents, which enabled the estimation of genetic correlations among different traits. (4) The genetic correlation of body weight (BW) measured under normal conditions and in the carcase experiment with the ascites indicator trait of right ventricle to total ventricle ratio (RV:TV) measured under cold conditions was 0.30. The estimated genetic correlation indicated that single-trait selecting for BW leads to an increase in occurrence of the ascites syndrome but that there are realistic opportunities of multi-trait selection of birds for improved BW and resistance to ascites. (5) Weak but positive genetic relationships were found between feed efficiency and ascites-related traits suggesting that more efficient birds tend to be slightly more susceptible to ascites. (6) The relatively low genetic correlation between BW measured in the carcase or in the feed efficiency experiments and BW measured in the ascites experiment (0.49) showed considerable genotype by environment interaction. (7) These results indicate that birds with high genetic potential for growth rate under normal temperature conditions have lower growth rate under cold-stress conditions due to ascites.

Animal Nutritional Physiological Phenomena↗

PubMed2005

Bacillus cereus var. toyoii and Saccharomyces boulardii increased feed efficiency in broilers infected with Salmonella enteritidis.

1. The effect on feed efficiency of two probiotics, one prepared with Saccharomyces boulardii and the other with Bacillus cereus var. toyoii, was tested in broilers infected with Salmonella enteritidis. 2. One-day-old chicks were divided at random into three groups and fed commercial feed devoid of antibiotics: group 1 was fed with non-supplemented feed, group 2 was supplemented with S. boulardii and group 3 with B. cereus. At 14 d of age the animals were challenged by the oral route with 1 x 10(7) viable S. enteritidis. 3. At d 47, average live weights were: group 1, 1.77 kg, group 2, 1.89 kg and group 3, 2.06 kg, and were significantly different. Feed conversion rates were 2.61 for group 1, 2.35 for group 2 and 2.30 for group 3. 4. We conclude that both probiotics improved feed efficiency in broilers.

Animal Feed↗

PubMed1975

Influence of genetic differences in feed efficiency of young chickens on derivation of metabolizable energy from the diet and nitrogen retention.

The relationship of efficiency of efficiency of feed utilization with metabolizable energy derived from the diet and nitrogen retention was studied in broiler strains and in lines selected for divergence in feed conversion ratio. Individual feed conversion (g feed/g gain) and metabolizable energy derived from the diet and nitrogen retention (determined by chromic oxide method) of these strains and lines were measured, and correlations were determined at various intervals from 4 to 9 weeks of age to determine the effects of age, sex, strain, feed conversion, growth, and feed consumption on the metabolizable energy derived from the diet and nitrogen retained. Although there were significant differences in feed conversion between sexes, strains, and lines selected for divergence in feed conversion, there were no associated differences in metabolizable energy derived from the diet or in nitrogen retention. There were no significant correlations of consumption, growth, or feed conversion with metabolizable energy derived from the diet or nitrogen retention. Nitrogen retention of the White Plymouth Rock strain was significantly higher for all ages. These results show that differences observed in growth, consumption, or feed conversion do not influence derivation of metabolizable energy from the diet or nitrogen retention.

Age Factors↗

PubMedDate not supplied

[The effect of the chronic administration of acetylsalicylic acid and acetaminophen on feeding efficiency in rats].

The influence was studied of the administration of acetylsalicylic acid and acetaminophen in doses of 450 mg/kg body weight/day, and 600 mg/kg/day respectively on the alimentary efficacy coefficient (AEC), on growth and on the hepatosomatic index in rats on a diet sufficient in all nutrients required to meet the animal's needs. The AEC was studied both for the whole experimental period and at values taken weekly. The results show that both aspirin and paracetamol significantly reduce overall alimentary efficacy (p < 0.05) and increase the hepatosomatic index. Partial AEC values showed that the analgesics studied significantly affect the figures (p < 0.05) for the intermediate periods (aspirin, 0.27 +/- 0.01, vs 0.38 +/- 0.03), and that these are more affected than those of the final treatment period (aspirin, 0.33 +/- 0.14, vs 0.36 +/- 0.07).

Acetaminophen↗

PubMed1993

Carcass composition, feed intake, and feed efficiency following long-term selection for four-week body weight in Japanese quail.

A study was conducted to determine BW, feed intake, feed efficiency, and carcass composition changes following 51 generations of selection for high 4-wk BW in Japanese quail. Quail lines utilized were the P line selected for high 4-wk BW on a normal 28% CP diet and the unselected base population (C line) from which the P line originated. Body weight, feed intake, and feed efficiency data were collected daily from 1 to 28 days, whereas percentage carcass water, ash, protein, and total lipid data were obtained at 0, 4, 7, 10, 14, 21, 28, 42, and 56 days of age. Body weights of P line quail were significantly (P < .05) larger than BW of C line quail at all ages with the greatest deviation occurring at the age of selection. Feed intake was significantly greater in the P line and paralleled BW increases. When feed intake was adjusted for differences in BW, P line quail consumed less feed per gram of BW than C line quail and adjusted feed intake declined with age after Week 1. The P line quail had superior feed efficiency compared with C line quail from 1 to 13 days of age with the greatest deviation immediately posthatch. Carcass composition determinations revealed significant (P < .05) age and line effects. Both percentage ash and protein increased from hatch to 14 days and thereafter remained constant. However, percentage water and total lipid demonstrated contrasting responses to increasing age; percentage water declined whereas percentage total lipid increased. The P line quail had less carcass water and protein, but had more lipid.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗

PubMed2006

Differential expression of mitochondrial and extramitochondrial proteins in lymphocytes of male broilers with low and high feed efficiency.

Studies were conducted to investigate relationships between mitochondrial and extramitochondrial protein expression, and protein oxidation in lymphocytes obtained from broilers in which individual feed efficiencies were obtained. Lymphocytes were isolated from male broilers from a single line that were shown to exhibit either low (0.48 +/- 0.02, n = 8) or high (0.68 +/- 0.01, n = 7) feed efficiency (FE). Western blot analysis showed that, compared with lymphocytes from high FE broilers, lymphocytes from low FE broilers exhibited a) higher amounts of oxidized proteins (protein carbonyls), b) lower amounts of 3 mitochondrial proteins [core I, cyt c 1 (complex III), and ATP synthase (complex V)], and c) higher amounts of 2 proteins [30 S (complex II) and COX II (complex IV)]. Two-dimensional gel electrophoresis revealed that the intensities of 25 protein spots from pooled samples of lymphocytes from high and low FE broilers differed by 5-fold or more. Three of these protein spots were picked from the gel and subjected to matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry analysis. One protein spot of ~33 kDa was tentatively identified by MALDI-TOF as a fragment of collapsin-2, a component of semaphorin 3D. The results of this study provide further evidence of increased oxidation associated with low FE and further evidence of differential protein expression associated with the phenotypic expression of feed efficiency.

Animal Feed↗