Backfat Deposition Research Articles

Progeny-testing of full-sibs IBD in a SSC2 QTL region highlights epistatic interactions for fatness traits in pigs

BackgroundMany QTL have been detected in pigs, but very few of them have been fine-mapped up to the causal mutation. On SSC2, the IGF2-intron3-G3072A mutation has been described as the causative polymorphism for a QTL underlying muscle mass and backfat deposition, but further studies have demonstrated that at least one additional QTL should segregate downstream of this mutation. A marker-assisted backcrossing design was set up in order to confirm the segregation of this second locus, reduce its confidence interval and better understand its mode of segregation.ResultsFive recombinant full-sibs, with genotype G/G at the IGF2 mutation, were progeny-tested. Only two of them displayed significant QTL for fatness traits although four inherited the same paternal and maternal chromosomes, thus exhibiting the same haplotypic contrast in the QTL region. The hypothesis of an interaction with another region in the genome was proposed to explain these discrepancies and after a genome scan, four different regions were retained as potential interacting regions with the SSC2 QTL. A candidate interacting region on SSC13 was confirmed by the analysis of an F2 pedigree, and in the backcross pedigree one haplotype in this region was found to mask the SSC2 QTL effect.ConclusionsAssuming the hypothesis of interactions with other chromosomal regions, the QTL could be unambiguously mapped to a 30 cM region delimited by recombination points. The marker-assisted backcrossing design was successfully used to confirm the segregation of a QTL on SSC2 and, because full-sibs that inherited the same alleles from their two parents were analysed, the detection of epistatic interactions could be performed between alleles and not between breeds as usually done with the traditional Line-Cross model. Additional analyses of other recombinant sires should provide more information to further improve the fine-mapping of this locus, and confirm or deny the interaction identified between chromosomes 2 and 13.

Cellularity of developing subcutaneous adipose tissue in Landrace and Meishan pigs: Adipocyte size differences between two breeds

Experiments were designed to compare the adipocyte cellularity of subcutaneous adipose tissue between growing Landrace (low backfat) and Meishan (high backfat) pigs at 1 week, 3 weeks, 6 weeks, 3 months and 5 months of age. As pigs aged, body weight and backfat thickness of both breeds significantly increased. When compared at equal ages, backfat thickness adjusted to equal body weight was greater for Meishan pigs. The mean diameter of fat cell size also increased with age, and by 6 weeks adipocytes from both outer and inner layers of subcutaneous adipose tissue were larger in Meishan pigs. At 5 months, approximately 80% of the adipose tissue mass in Meishan pigs was attributable to adipocytes measuring 95-165 µm in diameter, whereas adipocytes of 75-145 µm comprised most of the tissue mass in the Landrace. Although the contribution of smaller adipocytes (25-45 µm) to the tissue volume was negligible, both breeds showed a biphasic diameter distribution at all ages, suggesting that adipocyte hyperplasia is still active. Our results demonstrate that cellularity differences exist between the subcutaneous adipose tissues of Landrace and Meishan pigs, and adipocyte hypertrophy is the most overwhelming contributor to the greater backfat deposition for Meishan pigs.

SINE indel polymorphism of AGL gene and association with growth and carcass traits in Landrace × Jeju black pig F2 population

Genetic polymorphisms in the glycogen debrancher enzyme (AGL) gene were assessed with regard to their association with growth and carcass traits in the F2 population crossbred Landrace and Jeju (Korea) Black pig. Three genotypes representing the insertion and/or deletion (indel) polymorphisms of short interspersed nuclear element were detected at frequencies of 0.278 (L/L), 0.479 (L/S), and 0.243 (S/S), respectively. The AGL S allele-containing pigs evidenced significantly heavier body weights at birth, the 3rd week, 10th week, and 20th week during developmental stages and higher average daily gains during the late period than were noted in the L/L homozygous pigs (P < 0.05), respectively. However, average daily gains during the early period were not significantly associated with genotype distribution (P > 0.05). With regard to the carcass traits, the S allele pigs (S/-) evidenced significantly heavier carcass weights and thicker backfat than was measured in L/L homozygous pigs (P < 0.05). However, body lengths, meat color, and marbling scores were all found not to be statistically significant (P > 0.05). Consequently, the faster growth rate during the late period and backfat deposition rather than intramuscular fat deposition cause differences in pig productivity according to genotypes of the AGL gene. These findings indicate that the AGL genotypes may prove to be useful genetic markers for the improvement of Jeju Black pig-related crossbreeding systems.

Porcine skeletal muscle differentially expressed gene CMYA1: isolation, characterization, mapping, expression and association analysis with carcass traits

To investigate the differences in gene expression between some obese and lean pig breeds, differential display of mRNA was employed in our previous research. One differentially expressed EST (BI596262) was further identified as the porcine cardiomyopathy associated 1 (CMYA1) gene because of its homology to the human CMYA1 gene. The full-length DNA of the porcine CMYA1 gene encompasses 9379 bp, including a complete open reading frame encoding 1839 amino acid residues, a 158-bp 5'-untranslated region and a 630-bp 3'-untranslated region. The porcine CMYA1 gene was assigned to chromosome 13 by the radiation hybrid panel (IMpRH). The porcine CMYA1 gene was expressed only in the striated muscle. Single nucleotide polymorphism (SNP) scanning in the coding region identified one synonymous mutation (c.1053C>T) and three missense mutations, c.1394A>G (p.His465Arg), c.1751A>G (p.Asp582Gly) and c.3290C>A (p.Thr1097Asp). The allele frequencies were tested among about 200 unrelated pigs from several pig breeds. Linkage mapping was further conducted with the SNP c.1751A>G (p.Asp582Gly) in a Berkshire x Yorkshire resource family and this confirmed that porcine CMYA1 is closely linked with Sw344 (distance = 2 cM, LOD score is 129.47), an interesting region harbouring a QTL for back fat thickness. Association analysis in our experimental pig population showed that different genotypes of CMYA1 gene were associated with different back fat thicknesses (P < 0.05). Our results suggest that the porcine CMYA1 gene has effects on porcine back fat deposition and further investigation will be necessary to illustrate the underlying mechanisms.

Effects of Lower Dietary Lysine and Energy Content on Carcass Characteristics and Meat Quality in Growing-finishing Pigs

Fifty-four PIC barrows were used to evaluate the effects of lower dietary lysine content and energy level on carcass characteristics and meat quality in slaughter pigs. Pigs were allotted to one of three treatments by body weight with six replicate pens in each treatment. The dietary treatments for body weights of 20-50 kg, 50-80 kg and 80-90 kg were as follows, respectively: control diet (digestible energy 14.22 MJ/kg, lysine/DE 0.67 g/MJ, 0.53 g/MJ and 0.42 g/MJ); a low lysine group (digestible energy 14.22 MJ/kg, lysine/DE 0.49, 0.38 and 0.30 g/MJ); and a low lysine-low energy group or low nutrient group (digestible energy 13.11 MJ/kg, lysine/DE 0.49, 0.38 and 0.30 g/MJ). The daily weight gain, daily feed intake and feed efficiency were calculated in the overall growth period (nearly 12 weeks). Meanwhile, carcass characteristics and meat quality were evaluated at 60 and 90 kg body weight respectively. During the overall growth trial, lowering dietary lysine and nutrient level both decreased weight gain (p<0.05) and feed efficiency (p<0.01). At 60 kg body weight, decreasing dietary lysine and nutrient level noticeably decreased dressing percentage (p<0.01) and back fat depth at last rib of PIC pigs (p<0.01), but enhanced marbling scores (p<0.10), intramuscular fat content (p<0.10) and water loss rate (p<0.01) of the longissimus dorsi muscle. At 90 kg body weight, lean percentage (p<0.01) was evidently reduced by both lowering lysine content and nutrient level in the diet. However, the shoulder back fat depth (p<0.05) and marbling scores of the loin eye muscle (p<0.05) were increased; Lowering dietary nutrient level could improve back fat depth of 10th rib (p<0.01) and last rib (p<0.01), intramuscular fat content (p<0.10), redness (p<0.01) and water loss rate of the loin eye muscle (p<0.05), but decrease loin area (p<0.05). Finally, when comparing the 60 kg and 90 kg slaughter weights, it was found that the shoulder back fat depth (p<0.01, p<0.10), 6th-7th rib (p<0.01, p<0.01), 10th-rib (p<0.01, p<0.01) and last rib back fat depth (p<0.01, p<0.01) of the low lysine and low nutrient group were all obviously increased comparing with the control group. Taken together, the results showed that decreasing dietary lysine content and nutrient level increased intramuscular fat content and water loss rate of longissimus dorsi muscle; On the other hand, both lowering dietary lysine and nutrient level markedly compensated to increase back fat deposition in the later finishing period (body weight from 60

Características endocrinas, moleculares y de parámetros de crecimiento asociados a la obesidad del cerdo Pelón Mexicano

To establish the potential of the Mexican hairless pig as an animal model for the study of obesity, a comparative study between the Mexican hairless pigs (MHP) and Landrace-Yorkshire pigs (LYP) was performed. Leptin and insulin serum concentrations were measured and its correlation with backfat thickness was estimated. Feed intake, daily weight gain and backfat thickness was evaluated. Gene expression of leptin, leptin receptor, adiponectin and peroxisoma proliferator activated receptor gamma (PPAR-I³,) in adipose tissue were also evaluated. The LYP had a higher weight gain (P 0.05). However, the backfat thickness was higher in the MHP (P<0.01). A correlation of 0.73 between leptin concentrations and backfat thickness was found in the MHP (P<0.01) and a correlation of 0.75 in the LYP (P<0.01). However, the insulin concentrations only showed a positive correlation of 0.43 with backfat thickness in the MHP (P<0.05). The MHP showed higher gene expression for adiponectin, leptin and leptin receptor (P<0.05), but no differences were found for the gene expression of PPAR-I³, between groups. The Mexican hairless pigs showed a higher capacity for backfat deposition, higher leptin and insulin serum concentrations and higher expression of the genes associated with obesity. These results suggest that Mexican hairless pigs could be a better animal model for the study of obesity than Landrace-Yorkshire pigs.

Behaviour influences cholesterol plasma levels in a pig model

Little is known about the relationship between feed intake behaviour and cholesterol levels in humans. This can be attributed to the fact that feed intake behaviour in humans is difficult to assess. The relationships between feed intake, feed efficiency and feed intake behaviour, and cholesterol and triglyceride levels were investigated at an average age of 187 days, in a pig model consisting of 202 Duroc barrows. Feed intake and feed intake behaviour were recorded individually and daily by means of an electronic identification system. Animals with high levels of total cholesterol also had high levels of high-density lipoprotein (HDL), low-density lipoprotein (LDL) cholesterol and triglycerides. Animals with high levels of HDL also had high levels of LDL and triglycerides, and animals with high levels of LDL also had high levels of triglycerides. Animals with higher BW, higher backfat thickness, higher BW gain, higher gain of backfat deposition, higher feed intake, higher residual feed intake (RFI) and higher feed intake rate had higher levels of total, HDL and LDL plasma cholesterol. Results indicate that the relationship between feed intake and cholesterol levels is a long-term relationship, while the relationship between RFI and cholesterol levels is more of a short-term nature. The relationship between intake rate and cholesterol plasma levels disappeared after correction for the amount of feed consumed. Results indicate that feed intake independent of metabolic BW, growth and fatness, i.e. ‘RFI’, was positively correlated with cholesterol plasma levels. This suggests that eating food over and above the maintenance and growth requirements constitutes a health risk independent of the level of fatness.

Enhancing pork flavor and fat quality with swine raised in sylvan systems: Potential niche-market application for the Ossabaw hog

Our global food supply becomes more vulnerable as we continue to lose diverse genetic resources. The Ossabaw hog is a feral breed that is unique to North America, a distant relative to the renowned Iberian hog and is considered an endangered swine breed. The objective of our farmer participatory project was to examine the meat and fat characteristics of Ossabaw hogs raised in alternative management systems for niche-market application. At one farm, eight Ossabaw pigs were randomly assigned to a grass pasture and fed a free choice corn–soy (CS) ration or placed in a mixed hardwood forest plot and provided free choice peanuts in the shells (P), alfalfa pellets (A) and mast from the mixed hardwoods (diet collectively referred to as PAM). The two diets had no effect on Ossabaw production data or pork quality characteristics; however, fat profiles were altered. Ossabaws weighed approximately 70 kg when harvested at 400 days and produced chops with small loin eyes (21–23 cm2) and minimal evidence of intramuscular fat deposits (1%). The unsaturated fatty acid (USFA) to saturated fatty acid (SFA) ratio improved from 1.6 to 2.6 (P&lt;0.01) as a result of feeding the PAM diet. Forest-finished Ossabaw pork was considered more flavorful by food critics and renowned chefs than that of conventionally fed animals. Mast from hardwoods offers the possibility of enhancing pork flavor for niche markets and using a renewable forest resource as a food source. For farm two, eight Ossabaw gilts and eight crossbred progeny (from European breeds) were randomly assigned to one of the two dirt-lots and fed free choice a CS ration or PA diet (same ration as mentioned above with no mast). Ossabaw hogs grew nearly one-third as fast as the crosses and weighed approximately 80% of the crosses' harvest weight at twice their age. Loin eye areas of the crosses were nearly twice as large as the Ossabaws while the subcutaneous back fat deposition was nearly half. Compared to the CS diet, the PA ration decreased SFA by 23% while polyunsaturated fatty acids (PUFA) increased by 60%. The USFA to SFA ratios improved from 1.5 to 2.2 (P&lt;0.01) when PA diets were fed. Differences (P&lt;0.05) in USFA profiles were observed for breed effects; Ossabaws had 8% higher levels of monounsaturated fatty acids and 18% lower PUFA levels than the crosses. When adjusted for breed effects, no differences in sensory characteristics for the CS versus PA diets were detected by a trained panel. Ossabaws were more flavorful than the crosses (2.3 versus 1.6); (P&lt;0.05).

Effects of estradiol implantation on growth, carcass traits and circulating concentrations of insulin-like growth factors (IGFs) and IGF-binding protein-3 in finishing barrows

Eighty crossbred barrows aged 120 to 141 days and weighing 71.2±0.8 kg were randomly divided into eight pens, after which each of 40 animals in four pens was implanted with 24 mg of estradiol-17β (E 2; Compudose®). The animals were allowed an unrestricted access to water and a finisher diet containing 16% crude protein and 3.4 Mcal DE/kg and slaughtered at 107.4±0.8 kg. Blood samples were obtained by jugular venipuncture at day 0 before the implantation and at days 21 and 42. Serum concentration of E 2 increased between days 0 and 21 after the implantation and declined to a level above that of day 0 ( P<0.01) by day 42. E 2 implantation caused a decrease ( P<0.01) in feed intake and backfat thickness and a tendency ( P=0.08) of decreased average daily gain. However, feed conversion efficiency (FCE; live weight gain/feed intake) did not change due to the implantation ( P=0.20). The E 2 implantation did not affect physicochemical characteristics of longissimus muscle including percentages of protein ( P=0.17) and fat ( P=0.43), 24-h pH ( P=0.39), drip loss ( P=0.99), L* (lightness; P=0.78) and a* (redness; P=0.49) values. Serum concentration of insulin-like growth factor (IGF)-I decreased between days 0 and 21 ( P<0.01) and also between days 21 and 42 ( P<0.05) in unimplanted pigs, but not in implanted pigs ( P>0.05), which resulted in a greater ( P<0.05) mean IGF-I concentration in the implanted vs. unimplanted group. By contrast, serum concentrations of IGF-II and IGF-binding protein-3 did not differ between the two groups ( P>0.05). In summary, results suggest that E 2 suppresses voluntary feed intake and backfat deposition without significantly affecting growth efficiency and muscle characteristics in barrows and that effects of E 2 may be partly mediated by IGF-I.

Genotypes of 5′-flanking region in porcine heat-shock protein 70.2 gene affect backfat thickness and growth performance in Duroc boars

The 5′-flanking region in heat-shock protein 70.2 gene ( HSP70.2) has been found to be associated with meat quality, birthweight, and semen quality in pigs. This study examines the relation between the genotype of five polymorphic sites in the 5′-flanking region of porcine HSP70.2 with backfat thickness and growth performance under different environmental conditions, especially the cool (low temperature 12–19 °C, high temperature 19–25 °C) and hot (low temperature 21–25 °C, high temperature 28–33 °C) seasons. A total of 216 Duroc boars were performance tested in both seasons using segregated early weaning entrance. Haplotypes of the 5′-flanking region of the animals were determined using the single nucleotide polymorphisms of their siblings and/or parents. Additionally, six haplotypes were found in the tested samples and used to construct 15 genotypes. The animals with the most prevalent nine genotypes were further analyzed to determine the interaction between genotype and season. Genotype significantly influenced backfat thickness ( P<0.001). Furthermore, the interaction of genotype and season was found to influence both backfat thickness ( P<0.01) and feed efficiency ( P<0.05). Most of the variation in backfat thickness and feed efficiency was caused by pigs of certain genotypes raised during the cool season. Taken together, we suggest that variation of backfat deposition under different weather conditions may occur in Duroc boars with different genotypes of the 5′-flanking region of HSP70.2.

Development of adjustment factors for backfat and loin muscle area from serial real-time ultrasonic measurements on purebred lines of swine.

We recorded serial real-time ultrasonic measurements of backfat and loin muscle area to assess the rate of change per unit of live weight and growth rate measured as the change in weight per day of age during the finishing stage of production. Barrows (648) and gilts (459) representing eight major U.S. pure breeds of swine were evaluated in the study. Real-time ultrasonic measurements of backfat and loin muscle area were collected at average live weights (LW) of 67.4, 80.3, 93.4, and 104.9 kg. Backfat was measured at the midline over the last rib (LR) and last lumbar vertebra (LL) and off the midline at the 3/4 point (BF10) over the 10th rib. Loin muscle area (LMA) images were collected from the right-hand side of each pig at the 10th rib. Deposition rates were calculated on an intrapig basis for the dependent scan variables BF10, LMA, LR, and LL in models that included the independent variables LW and LW2. For growth rate (WDA), LW was regressed on age and age. Intrapig linear regression coefficients and y-intercepts were further analyzed as dependent variables in a mixed model that included the fixed effects test group, sex, and breed and random effects of sire and dam nested within breed. Significant breed effects were present for deposition rates of BF10, LMA, LR, LL, and WDA. Across the eight breeds, BF10 was deposited at a mean of .271 +/- .008 mm/kg, a rate faster than the average for LR (.201 mm/kg) and LL (.206 mm/kg). The LMA deposition rate across breeds averaged .304 cm2/kg. Average WDA across the breeds was .774 kg. Barrows deposited fat faster at all locations, deposited muscle slower, and grew faster than gilts in this study (P < .001). The results of this study indicate a need for breed- and sex-specific adjustment factors for rates of backfat and loin muscle deposition and for weight per day of age in swine.

Possible hormonal activity of date pits and flesh fed to meat animals

Awassi lambs fed different levels of date by-products (date pits and flesh) were observed to gain body weight faster, have higher back fat thickness and less shrinkage per cent than their corresponding control. The weight gain and back fat deposition increased with the increase of the date by-products in the animal diets. Based on these observations it was hypothesized that these by-products may contain natural anabolic agents. Therefore, date pits aqueous extract was prepared and added to a rat's uterus suspended in an organ bath containing Dejalon's solution at 37 °C. The free end of the uterus was threaded to an isotonic transducer connected to a MD 2 Washington recorder. The extract induced uterus contraction and its effect was not blocked by atropine or cyproheptadine but partially by prostaglandin-synthesizing inhibitors, suggesting that the extract acts in a similar fashion to oestrogens.

The effects of the dietary inclusion of sida meal (Malvaceae) for gilts on the reproductive performance, apparent digestibility, rate of passage and plasma parameters

The objective of this experiment was to measure the effects of sida meal (a fibrous feedstuff) incorporated to a basal pregnancy ration at four levels, i.e. 0 (control), 5, 10 and 15% on the reproductive performance, apparent ileal and overall digestibility, rate of passage and some plasma parameters of gilts. Reproductive performance measured in terms of body mass changes, backfat deposition from service to service, litter size, piglet birth weight and average milk yield was not significantly influenced by adding sida meal. Plasma concentrations of total volatile fatty acids (VFA), acetic acid, propionic acid and butyric acid increased, while cholesterol levels tended to decrease with increasing intake of sida meal. Nitrogen retention increased with increasing intakes of sida meal, this may be mainly due to an increase in gut-fill with little or no effect on N bioavailability. Apparent ileal digestibilities of dry matter, neutral detergent fibre (NDF), Ca, P, leucine and cystine decreased linearly and significantly (P < 0.05) with increasing sida meal intakes. Also, there were similar negative responses of the apparent overall digestibilities of most of the proximate nutrients, minerals and amino acids to the graded levels of sida meal. Apparent overall digestibilities of dry matter (DM), N, acid detergent fibre (ADF), NDF, cellulose and lignin in sida meal amounted to 0.54, 0.68, 0.20, 0.26, 0.18 and 0.17, respectively. The energy value of this product, expressed in DE (MJ kg −1), was 8.89, i.e. equal to 8.24 MJ kg −1 of metabolizable energy.

Beta-Adrenergic Receptors and Adenylate Cyclase Activity in Heart, Muscle and Adipose Tissue of German Landrace Pigs Selectively Bred for Differences in Backfat Deposition

The density of beta-adrenergic receptors was examined in heart, muscle (m. longissimus dorsi) and backfat tissue of German Landrace pigs using (-)-[3H]-dihydroalprenolol. The animals were selected for high (E(+)-line) or low (E(-)-line) activity of lipogenic enzymes in backfat and for low backfat thickness (U(-)-line) based on ultrasonic measurement. An unselected control (K0-line) also exists. The correlated selection response on stress susceptibility (measured by halothane reaction and by meat quality parameters) showed the following sequence of selection lines: U- greater than E- greater than E+ greater than K0. The strains used for examination descended from the 9th generation (heart and muscle tissue) and the 10th generation (heart, muscle and adipose tissue) of this selection experiment. No further selection took place between the 9th and 10th generation. Basal adenylate cyclase activity was determined as well as (-)-Isoproterenol + GTP or sodium fluoride (NaF) stimulated activity in heart and muscle of the 10th generation measuring [3H]-cAMP formation from [3H]-ATP. A good correlation (r greater than or equal to 0.59, n = 9) between beta-adrenergic receptor density and adenylate cyclase activity was found which pointed to an efficient receptor-effector system. The number of beta-adrenergic receptors and adenylate cyclase activity was higher in the U(-)-line in all investigated tissues compared to the other lines in the 9th and 10th generation. Most differences between these lines were also significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of diet density and environmental temperature on performance and carcass quality of pigs fed ad libitum to bacon weight

Ad libitum feeding from hoppers offers a simple system for feeding growing pigs and maximises liveweight gain. High feed intake in the later stages of production often results in excessive backfat deposition, making it difficult to achieve optimum carcass gradings with pigs kept to bacon weight. Both nutrient density of the diet and ambient temperature may influence voluntary feed intake. This experiment investigated the extent to which these factors could be used under commercial conditions to manipulate growth rate and fat deposition of pigs on an ad libitum feeding system.

A comparison of two contrasting types of grain sorghum in the diet of the growing pig

ABSTRACTA study was undertaken to compare the chemical composition of Texas No. 2 hybrid yellow sorghum with that of a traditional brown-seeded variety and also their digestibility and nitrogen retention in the growing pig. Dry matter, crude protein and gross energy contents and amino acid composition were similar in the two varieties but brown-seeded sorghum had a markedly higher tannin content. In diets containing 70% of either yellow or brown sorghum, N retention was marginally higher on the yellow sorghum diet and apparent digestibility of dry matter, nitrogen and gross energy was improved (0·07, 0·06 and 0·12 units respectively). The improvements in digestible energy and crude protein content of the yellow sorghum diet over the brown-seeded one were 10% and 6% respectively. In a subsequent trial 16 pigs were individually and scale-fed each of the diets over the live-weight range 28 to 81 kg. Growth rates and feed conversion ratios were better on the yellow sorghum diet (10%) but sorghum variety did not influence killing-out percentage, deposition of backfat or area of eye muscle in cross-section.

A Note on the use of micronized barley for growing pigs

SummaryAn experiment was undertaken to examine the effects of the micronization process followed by grinding on the chemical composition of barley and on digestibility and nitrogen (N) retention in the growing pig. Micronization relative to normal grinding increased the dry matter (DM) content and starch availability in vitro and decreased the protein content of the cereal. Retention of N was not affected by the process but apparent digestibility of the DM, N and gross energy was improved. The improvement in digestible energy content of micronized barley over the ground grain was 3·8%. In a subsequent trial 24 pigs were individually and scale-fed a diet containing 75% of barley in ground or micronized and ground form over the liveweight range 33 to 80 kg. Processing treatment did not influence growth rate, DM food conversion ratio, killing-out percentage, deposition of backfat or area of ‘eye muscle’ in cross-section.

Body Weight and Backfat Deposition in Swine: Curves and Correction Factors

Body Weight and Backfat Deposition in Swine: Curves and Correction Factors

NUTRIENT REQUIREMENTS FOR CANADIAN YORKSHIRE SWINE: V. A STUDY OF THE LYSINE AND PROTEIN REQUIREMENTS OF FINISHING PIGS WEIGHING FROM 100 TO 200 LB

Ninety-six pigs (48 barrows, 48 gilts) were allotted according to sex and previous ration to three linear-programmed finisher rations: (1) 13% protein and 0.55% lysine, (2) 13% protein and 0.67% lysine, and (3) 16% protein and 0.67% lysine. Growth rates, digestibility coefficients for energy and protein, feed consumption, and carcass data were obtained.In terms of growth rates and efficiency of energy utilization 16% protein rations were superior to 13%, but increasing lysine from 0.55 to 0.67% with 13% protein rations was as effective as increasing the protein level. However when cross-sectional area of longissimus dorsi muscle and back fat deposition were considered, increasing the protein level was more effective than extra lysine in promoting a high lean:fat ratio.Evidence of an inverse relationship was observed between rate of gain during the growing period and rate of gain during the finishing period, particularly in barrows.