HP Line Research Articles

Comprehensive survey of transposon mPing insertion sites and transcriptome analysis for identifying candidate genes controlling high protein content of rice.

Rice is the most important crop species in the world, being staple food of more than 80% of people in Asia. About 80% of rice grain is composed of carbohydrates (starch), with its protein content as low as 7–8%. Therefore, increasing the protein content of rice offers way to create a stable protein source that contributes to improving malnutrition and health problems worldwide. We detected two rice lines harboring a significantly higher protein content (namely, HP5-7 and HP7-5) in the EG4 population. The EG4 strain of rice is a unique material in that the transposon mPing has high transpositional activity and high copy numbers under natural conditions. Other research indicated that mPing is abundant in the gene-rich euchromatic regions, suggesting that mPing amplification should create new allelic variants, novel regulatory networks, and phenotypic changes in the EG4 population. Here, we aimed to identify the candidate genes and/or mPing insertion sites causing high protein content by comprehensively identifying the mPing insertion sites and carrying out an RNA-seq-based transcriptome analysis. By utilizing the next-generation sequencing (NGS)-based methods, ca. 570 mPing insertion sites were identified per line in the EG4 population. Our results also indicated that mPing apparently has a preference for inserting itself in the region near a gene, with 38 genes in total found to contain the mPing insertion in the HP lines, of which 21 and 17 genes were specific to HP5-7 and HP7-5, respectively. Transcriptome analysis revealed that most of the genes related to protein synthesis (encoding glutelin, prolamin, and globulin) were up-regulated in HP lines relative to the control line. Interestingly, the differentially expressed gene (DEG) analysis revealed that the expression levels of many genes related to photosynthesis decreased in both HP lines; this suggests the amount of starch may have decreased, indirectly contributing to the increased protein content. The high-protein lines studied here are expected to contribute to the development of high protein-content rice by introducing valuable phenotypic traits such as high and stable yield, disease resistance, and abundant nutrients.

Focus on lasers, imaging, microscopy, and nanoscience

Focus on lasers, imaging, microscopy, and nanoscience

Polymorphisms of CSF1R and WISP1 genes are associated with severity of familial adenomatous polyposis in APC1311 pigs.

Hereditary familial adenomatous polyposis (FAP) in humans significantly increases the risk of development of colorectal cancer (CRC). Germline mutations in the APC (adenomatous polyposis coli) gene are responsible for FAP. Despite having the same causative mutation, the severity of the disease differs from patient to patient. The porcine FAP model carrying a truncating APC1311 mutation, orthologous to the dominant human mutation that leads to severe form of the disease (APC1309), mirrors the severity of polyposis. Earlier RNAseq studies have revealed the differential expression of WISP1 and CSF1R in samples derived from low-grade (LG-IEN) and more advanced high-grade (HG-IEN) colon polyps of APC1311/+ pigs. The grade of dysplasia was correlated with the severity of polyposis in APC1311/+ pigs characterized by a low (LP) and high (HP) numbers of polyps. The goal of this work was to find DNA variants that regulate the expression of CSF1R and WISP1 in LP and HP pigs. In total, 32 and 36 polymorphisms in CSF1R and WISP1 were found, respectively. Of these, the genotype frequency of four silent SNPs in the coding region of WISP1 differed significantly between LP and HP lines. In silico analysis revealed an elevated minimum free energy (MFE) for three of these SNPs, suggesting their role in mRNA structure stability. Furthermore, four polymorphisms in the promoter region of CSF1R, cosegregating as a common haplotype, were associated with polyp number in APC1311/+ pigs. A secreted alkaline phosphatase (SEAP) assay showed, however, that these variants have no direct effect on the activity of the CSF1R promoter. Concluding, our study identified polymorphisms in CSF1R and WISP1 that are potentially associated with the severity of polyposis in APC1311/+ pigs.

Guilan combined power plant in Iran: As case study for feasibility investigation of converting the combined power plant into water and power unit

This study aims to find a cost effective solution for converting an existing combined power plant into a CWP system including the membrane and thermal desalination units. Without applying major structural change in power plant, to supply fresh water, the steam lines extracted from heat recovery steam generator are used in the thermal desalination unit and membrane desalination system is connected to the gas turbine. An investigation is performed on the produced water and performance of power plant associated with different conditions of electricity and water demands. Also, the influence of steam corresponding to the low and high enthalpy conditions on the performance of thermal desalination unit and power plant is explored. Furthermore, in view of the production capacity of electricity associated with the gas units and consumption demands of various seasons, the influence of membrane desalination unit on the water production is illustrated. An economic investigation is performed to estimate the selling price of water in each unit. It is concluded that in the thermal unit, using HP line produces about 25,000 m3/day, while the LP line causes up to 7000 m3/day water.

In Vitro and In Vivo Effects of West Nile Virus Propagated in Cells of Different Passage

Tissue cultures are used to propagate viruses for use in mosquito infection studies and to detect live virus in field-collected specimens. Microscopic evaluation of cytopathic effects is used to visualize virus presence. In this study, both low-passage (LP; n = 35) and high-passage (HP; n = 218) lines of African green monkey kidney (Vero) cells were infected with West Nile virus, and virus growth kinetics were quantitated over different incubation periods (IPs) (2, 6, 10, 24, 48, 72, and 96 h postinfection). Virus titers were significantly (P < 0.05) higher in the HP compared with LP line 24, 48, and 96 h postinfection. No differences were observed in plaque morphology between the LP and HP lines. Culex pipiens quinquefasciatus were fed infectious blood meals created using supernatant from the 2 lines and maintained at 28 degrees C for a 12-day IP. Although the virus dose was higher (P < 0.05) in the HP compared with the LP line, there were no significant differences in mosquito infection or dissemination rates at the end of the IP. The significance of these observations for assessing virus presence and pathogenicity is discussed.

Sclereid development during fruit ripening in two lines of Tabasco pepper (Capsicum frutescens)

Fruit development was examined in two lines of Tabasco pepper (Capsicum frutescens) which had previously been selected for hard-to-pick persistent fruit (HP) or easy-to-pick (EP) fruit. Four plants of each line were grown under glass. Random selections of ten flowers of each line were tagged at three or four-day intervals until the first-tagged flowers were in the “mature red” harvest condition. At that point all samples were collected and paraffin-processed for anatomical examination. Cells in the separation zone were examined morphometrically to determine the rate of sclerenchyma differentiation. Although cells in both the central and peripheral regions of the separation zone become sclerified in both lines, sclereid differentiation is faster and more complete in the HP line. In both lines sclerenchyma in the peripheral zone matured significantly faster than sclerenchyma in the corresponding central zone. Although degree of sclerification may have some role in tenacity of the HP fruit to the subtending pedicel, it does not correlate strongly with detachment force, especially in the EP line.

Effect of Selection for Increased Body Weight and Increased Plasma Yolk Precursor on Developmental Stability in Japanese Quail

Developmental stability of several Japanese quail lines was measured by bilateral asymmetry. Lines included in the study were as follows: a randombred control (R1), sublines of R1 selected for increased (HW line) and decreased (LW line) 4-wk BW, and sublines of R1 selected for increased (HP line) or decreased (LP line) total plasma phosphorus (TPP; a measure of yolk precursor in the blood) at the beginning of lay. In sublines of the HW line, the males were selected for increased 4-wk BW and the females for increased (HW-HP line) or decreased (HW-LP line) TPP. The HW, LW, HP, and LP lines were in their 41st generation of selection and the HW-HP and HW-LP lines in their 31st generation of selection. The number of birds in each line and sex subgroup was 30.The adult breeders (28 to 32 wk of age) were weighed and killed, and bilateral measurements were made of shank length, width (laterally at the dew claw), and depth (perpendicular to the dew claw), face length, and pectoralis major and p. minor weights. Data on asymmetry was expressed for the right side minus the left side as signed and absolute differences. In order to correct for the correlation between trait size and asymmetry, relative asymmetry (RA) was obtained by dividing the absolute differences between sides by the average value of both sides and multiplying by 100.All lines differed in BW at 4 wk of age with the ranking HW > HW-LP > HW-HP > LP > R1 > HP > LW. Line rankings of adult breeders were similar, except the HP and LP lines did not differ from the R1 line and the order of ranking of the HW-HP and HW-LP lines was opposite that at 4 wk of age. Line differences in signed and absolute differences were significant for most bilateral traits. However, after adjustment for trait size, line differences in RA were less frequent. In general, there were few significant differences in RA for the R1 line versus the selected lines, even though inbreeding of the R1 line (19%) was less than half that of the selected lines (44 to 57%), suggesting that homozygosity did not influence developmental stability. Selection for increased or decreased BW had little influence on RA. Developmental stability tended to be higher in the lines (LP and HW-LP) selected for decreased TPP. The data indicated that bilateral asymmetry was not a good measure of developmental stability in the current study.

Divergent selection on feather pecking behaviour in laying hens ( Gallus gallus domesticus)

A selection experiment was initiated in 1996 in which selection for (HP line) and against (LP line) feather pecking was performed. The foundation stock was a White Leghorn layer strain established in 1970 and maintained since then as a random bred control line at the Institute. Six hatches were produced over three generations. At the age of 68 weeks (generation 0, 1996), 35 weeks (generation 1, 1997), 30 weeks (generation 2, 1998), and 27 weeks (generation 3, 1999) female birds were transferred to observation pens and their feather pecking behaviour was recorded. In each generation, 30 females and 8 males were selected from approximately 200 females and 60 males. The selection criterion was breeding value estimated by animal model on the trait ‘number of bouts of feather pecking per bird per hour’. Feather pecking behaviour in adult hens was significantly higher in HP than in LP. In generation 2 the following was recorded: 3.10 versus 1.37 bouts per bird per hour ( P<0.01), 7.04 versus 3.58 pecks per bird per hour ( P<0.05) and the proportion of hens recorded feather pecking in the 180 min observation period was 67 versus 56% ( P<0.05). In generation 3 the following was recorded: 4.56 versus 0.63 bouts per bird per hour ( P<0.001), 13.9 versus 2.51 pecks per bird per hour ( P<0.001) and the proportion of hens recorded feather pecking in the 180 min observation period was 75 versus 49% ( P<0.001). In generation 3, plumage condition was better in LP on neck, breast, back, wings and tail, as well as overall ( P<0.001). Body weight did not differ between lines in generation 2, but in generation 3, HP hens were on average heavier than LP hens at the age of 27 weeks (1435 g versus 1371 g, P<0.001).

Effect of divergent selection for total plasma phosphorus on plasma and yolk very low density lipoproteins and plasma concentrations of selected hormones in laying Japanese quail

Japanese quail lines were divergently selected over 32 generations for laying hen plasma yolk precursor, as measured by total plasma phosphorus (TPP). The high (HP) and low (LP) lines were developed from a randombred control population (R1) that was maintained without conscious selection. The purpose of the present study was to characterize the composition of very low density lipoproteins (VLDL) in laying Japanese quail hens (VLDLy) and the concentration of selected hormones in laying hens from the HP, LP, and R1 lines. The changes in TPP because of genetic selection in the Japanese quail lines were associated with large alterations in plasma VLDLy concentration (HP > R1 > LP), but only minor changes in lipid composition and size (HP > LP = R1; P< or =0.01) of plasma VLDLy particles. Basal plasma levels of hormones associated with reproduction and lipid metabolism were also different among lines, with luteinizing hormone (LH) ranking HP >R1 = LP and triiodothyronine (T3), thyroxine (T4), and 17beta-estradiol ranking HP > R1 > LP (P< or =0.05). The results suggest possible increased rates of hepatic lipogenesis, hepatic VLDLy assembly and secretion, and plasma VLDLy concentration in association with increases in concentrations of plasma LH, T3, T4, and 17beta-estradiol. Concentrations of total lipids in yolk VLDL were not different among lines, and only minor line differences in the concentration of different classes of yolk VLDL neutral lipids were detected. The data indicate a preferential uptake of a specific plasma VLDLy subpopulation into rapidly growing ovarian follicles, resulting in a constant composition of yolk VLDL of laid eggs among lines of Japanese quail with large differences in plasma VLDLy concentration.

Analysis of genetic polymorphisms in the major histocompatibility complex of Japanese quail

The restriction fragment length polymorphisms (RFLP) of the Japanese quail MHC were assayed in seven lines using PvuII-digested DNA and a chicken Class II probe. The lines of Japanese quail surveyed included a randombred control population (R1) and sublines of R1 divergently selected for 4-wk body weight (HW and LW lines) or plasma yolk precursor as measured by total plasma phosphorus (TPP) (HP and LP lines). In addition, two sublines (HW-HP and HW-LP) of the HW line were included in the analysis. Males of both sublines were selected for increased 4-wk body weight whereas the females were selected for increased (HW-HP) or decreased (HW-LP) TPP. The number of birds surveyed per line ranged from 13 to 16. The chicken probe used produced discernible bands or fragments using Southern blot analysis. There were 16 different RFLP patterns as well as 7 different heterozygote patterns detected in the various Japanese quail lines. The band or fragment number of each pattern varied from 7 to 15. A total of 28 different bands or fragments were seen in the RFLP patterns and only 2 bands or fragments were common to all 16 patterns. The distribution of the RFLP patterns differed greatly among the Japanese quail lines. The R1 line differed in frequency of the patterns from all of the selected lines. The divergently selected lines (HW vs LW; HP vs LP; and HW-HP vs HW-LP) also differed in the frequency of the various RFLP patterns. In the comparison of the HW and LW lines, there were no RFLP patterns in common between the two lines. The results of the present study indicated that the Japanese quail MHC Class II genes were highly polymorphic.

Measurement of genetic variation within and between Japanese quail lines using DNA fingerprinting

The objective of the present experiment was to study genetic variation within and among well-defined Japanese quail lines by DNA fingerprinting. The Japanese quail lines included a randombred control line (R1) and lines developed from R1 by divergent selection over 30 generations for 4-wk BW (HW, LW) and total plasma phosphorus (TPP) (HP, LP), a measure of yolk precursor in the blood. In addition, two sublines (HW-HP, HW-LP) of HW, developed in the ninth generation, were included in the analysis. Males of the sublines were selected for increased 4-wk BW whereas females were selected for increased (HW-HP) or decreased (HW-LP) TPP. Sixteen individual DNA samples per line were digested with HaeIII restriction enzyme and hybridized with Jeffreys' 33.6 probe. The DNA fingerprints were analyzed with computer programs designed to measure band sharing (BS). Within lines, BS ranged from 0.384 to 0.525. The BS within the R1 line was less than that of all selected lines, except for the HP and LP lines, indicating that, in general, selection had increased genetic homogeneity within the selected lines. Between lines, BS was less than within lines and the R1 line had the highest average level of BS (0.278) with the other lines. The BS between lines for the selected lines ranged from 0.230 to 0.308 with an average of 0.265. In the comparison of the R1 line with the selected lines, it appeared that selection for increased TPP or decreased BW may have influenced BS levels. The relationships of the HW line with its sublines (HW-HP and HW-LP) were not accurately predicted by the DNA fingerprinting technique used. All lines were separated, as indicated by the genetic distance between lines.

The effect of divergent selection for total plasma phosphorus in Japanese quail on fearfulness and selected blood and heart parameters

A selection experiment utilizing Japanese quail was initiated to study the genetic relationship of growth and reproduction traits. In this study, lines were selected for increased (HP line) and decreased (LP line) total plasma phosphorus at the beginning of lay. The HP and LP lines were derived from a randombred control population (R1 line) that was maintained with the selected lines to remove environmental variation over generations. During the course of selection, it was observed that blood from HP line females was more viscous than that of the LP and R1 females. In later generations of selection, mortality of females during a 120-d egg production period was higher in the HP line than in the LP and R1 lines. The purpose of this experiment was to identify possible factors contributing to the increased mortality in the HP line. Fearfulness, as measured by tonic immobility, was greater in the HP and LP lines than in the R1 line. Indirect blood pressure measurements were made near the beginning and near the end of the 120-d egg production period. No significant line differences were observed in either measurement. Weight of the heart at the end of the laying period was higher in the HP and LP lines than in the R1 line. Histological study of the hearts of the HP and R1 lines indicated significant increases in the HP line in collagen content of the coronary arteries and in myocardial fibrosis. The data suggest that the increased mortality of females of the HP line relative to the R1 line during the laying period may be related to increased fearfulness and changes in the coronary structure leading to heart abnormalities.

Moderately increased constitutive proline does not alter osmotic stress tolerance

Proline‐overproducing carrot cell lines were isolated by selection in medium containing hydroxyproline, a toxic analogue of proline. During growth of the cells in culture, length of lag phase, doubling time, and maximum fresh weight were the same for the hydroxyproline‐resistant cell line (HP) and the wild‐type cell line (JW). Proline content and resistance to hydroxyproline in the HP and JW lines were not strictly correlated indicating that another reason besides the constitutive level of proline is involved in hydroxyproline resistance. Tolerance to polyethylene glycol‐induced desiccation stress was not different between the two lines except perhaps at the early stages of culture growth when the proline levels of the two cell lines were nearly the same. The complexity of the relationship between proline accumulation and osmotolerance is discussed and strategies to achieve constitutive high levels of proline accumulation in plants are proposed.

Divergent selection for body weight and yolk precursor in Coturnix coturnix japonica. 12. Heterosis in reciprocal crosses between divergently selected lines

A selection experiment was started using Japanese quail to study the genetics of BW and plasma yolk precursor (measured by total plasma phosphorus; TPP). Lines were divergently selected for 4-wk BW (HW and LW) or plasma TPP (HP and LP). Sublines of HW were developed by continuing to select the males for increased 4-wk BW while selecting the females for increased (HW-HP line) or decreased (HW-LP line) TPP. The purpose of the present study was to determine the inheritance of traits associated with growth and reproduction in reciprocal crosses between the divergently selected lines and sublines. Reciprocal crosses were made between the HW and LW, HP and LP, and HW-HP and HW-LP lines. Traits measured included BW at various ages, age at sexual maturity, egg production, ovarian follicular development, egg weight, TPP, wet and dry liver weights, and occurrence of smooth muscle tumors in the ligaments of the oviduct. The HW line differed from the LW line in all traits measured except TPP and weight of smooth muscle tumors. No offspring were obtained from the HW x LW matings (male listed first). In the LW x HW cross, heterosis was negative for BW through sexual maturity and age at sexual maturity. Positive heterosis was observed for egg production, egg weight, and occurrence of smooth muscle tumors. Differences between the HP and LP lines were observed in the selected trait (TPP) and some correlated traits (BW at some ages, age at sexual maturity in females, egg production, and number and total weight of ovarian follicles). Positive heterosis in the HP and LP crosses was observed for BW, egg production, egg weight, and number of ovarian follicles whereas negative heterosis was observed for TPP and age at sexual maturity in females. The HW-HP and HW-LP lines differed in the selected traits and some correlated traits (egg weight and weights of the liver and smooth muscle tumors). Positive heterosis in the crosses was observed for BW, egg production, and liver weights whereas negative heterosis was evident for age at sexual maturity and TPP.

Divergent Selection for Body Weight and Yolk Precursor in Coturnix coturnix japonica.: 11. Correlated Responses Over Thirty Generations

Japanese quail lines were divergently selected for 4-wk BW (HW and LW lines) and plasma yolk precursor [total plasma phosphorus (TPP); HP and LP lines] for 30 generations. The base population was a randombred control line (R1) that was maintained along with the selected lines. Sublines were established from the ninth selected generation of HW by continuing to select males for increased 4-wk BW and selecting females for increased (HW-HP line) or decreased (HW-LP line) TPP. Correlated responses over the entire selection period were measured.Egg production of HW, LW, HP, and HW-HP declined over generations. There was a positive quadratic component to the change in HW indicating that the change in egg production over generations was decreasing. There was no significant change in egg production of LP. Number of ovarian follicles in rapid development increased in LP and decreased in LW and HP, Total follicular weight increased in HW and LP and decreased in LW. Production of abnormal eggs increased over generations in HW and HW-HP.Body weight at the beginning and end of the laying period increased in HW, HW-HP, HW-LP, and LP and decreased in LW. Egg weight increased in HW and HW-HP and decreased in LW and LP. The increase in egg weight of HW was due to a disproportionate increase in shell and yolk. Wet weight of the liver increased in HW and decreased in LW and HP. Dry liver weight decreased in LW, HP, and LP. Mortality to 4 wk of age increased in LW, HP, and LP.

Divergent Selection for Body Weight and Yolk Precursor in Coturnix coturnix japonica.: 10. Response to Selection Over Thirty Generations

Japanese quail lines were divergently selected for 30 generations for 4-wk BW (HW, LW) or plasma yolk precursor (HP, LP) as measured by total plasma phosphorus (TPP) at the beginning of lay. The HW, LW, HP, and LP lines were initiated from a randombred control line (R1). In the ninth generation of selection in the HW line, sublines were developed by continuing to select males for increased 4-wk BW whereas females were selected for increased (HW-HP line) or decreased (HW-LP) TPP. Individual selection was used in the HW, LW, HW-HP, and HW-LP lines. In the HP and LP lines, females were individually selected whereas males were selected on their full-sisters’ performance.Realized heritabilities (h2), based on the linear regression of selection responses (corrected for environmental changes) on accumulated selection differentials (weighted for the number of offspring produced) over generations, declined with selection in the HW, LW, HP, and LP lines. The h2 of 4-wk BW in the HW line was 0.42 during the first 10 generations of selection and then declined to 0.30 during the next 20 generations of selection. In the LW line, realized h2 of 4-wk BW was 0.40, 0.16, and −0.12 in Generations 1 through 10, 11 through 20, and 21 through 30, respectively. The respective h2 for TPP in the HP line were 0.29, 0.17, and 0.14. The h2 of TPP in the LP line was 0.35 during the first 10 generations and essentially zero during the next 20 generations.Four-week BW and TPP were negatively associated in the HW, HP, and LP lines. There was no significant relationship between these two traits in the LW line.

Selection for High Eight-Week Body Weight in Normal and Dwarf Chickens Under High-Protein and High-Energy Diets

A study was conducted to examine genetic parameters associated with selection for high 8-wk BW in normal and dwarf Athens Canadian randombreds under two nutritional environments (high protein and high energy) and to determine the influence of the selection diet on subsequent water to feed ratios and abdominal fat levels. High-protein lines (HP) received a diet containing 25% CP and 3,100 kcal ME/kg, whereas high-energy lines (HE) received a 22% CP diet containing 3,200 kcal ME/kg. Body weights, selection gains, selection differentials, and heritabilities were similar for normal HP and HE lines. There was evidence, however, that the realized heritability was greater in the HE than the HP dwarf line. Similar selection differentials indicate that this difference was apparently due to the expression of greater genetic variation in the HE dwarf line. Water intake, feed intake, water to feed ratio, and abdominal fat data for the four lines under “selection” and “reciprocal” environments differed between experiments. In Experiment 1, when fed the HE diet, normal birds selected under the HP environment had higher (P < .05) water to feed ratios and lower abdominal fat levels than contemporaries selected under the HE diet. However, these differences were not significant in Experiment 2.

Direct and correlated responses to three S1-recurrent selection strategies for increasing protein yield in oat

The objectives of this study were to evaluate the efficacy of S1-recurrent selection for increasing groat (caryopsis)-protein yield in oat (Avena sativa L.) and to compare the effects of three selection strategies on correlated responses in groat yield and groat-protein concentration. Three S1-recurrent selection programs were conducted for five cycles. Selection criteria in each program (line of descent) emphasized different components of protein yield; high grain yield in HG, both high grain yield and high groat-protein concentration in HP, and protein yield per se in HGP. Thirty to sixty random S0-derived lines from each cycle and ten check lines were evaluated in one year at two locations to estimate the response to selection. Groat-protein yield increased 4.4% cycle-1 in HG, 3.4% cycle-1 in HP, and 2.2% cycle-1 in HGP. Gains in groat yield were 7% cycle-1 in HG, 1% cycle-1 in HP, and 3% cycle-1 in HGP. Mean groat-protein yield and groat yield in the cycle 5 (C5) populations of all three lines of descent were equal to or slightly higher than those of high yielding cultivars. The HG line of descent showed a significant decrease from 193 to 175 g kg-1 groat protein, while the HP line of descent showed a significant increase from 202 to 218 g kg-1. The HGP line of descent showed a small but significant decline in groat protein from 200 to 192 g kg-1. In comparison, the high-protein commercial cultivars contained about 210 g kg-1 groat protein. The C5 population of the HP line of descent had a unique combination of high groat yield and high groat-protein concentration. Genotypic variances for groat-protein yield, groat yield, and groat-protein concentration were not always significant in the various cycles of the three lines of descent, but in no instance was there a consistent change from C0 to C5. S1-recurrent selection was effective for increasing groat-protein yield of oat, and with the proper germplasm and selection strategy both groat yield and groat-protein concentration can be improved simultaneously.

Effect on Carcass Traits of Selection for Increased Lean Tissue Growth Rate in Swine on Low or High Dietary Protein Levels

Pigs were selected for lean tissue growth rate (LTGR) in two lines, fed low (LP line) or high (HP line) protein levels. This investigation comprised 92 and 95 pigs, respectively, from generation 3 of the two lines, tested on low, medium and high protein diets between 25 and 105 kg body weight. HP compared to LP line pigs had higher ham percentage (P=0.02), thinner backfat (P=0.003) and lower intramuscular fat content (P = 0.01). A positive correlated response (P=0.02) in osteochondrosis score of femur (OCDf) was found in the HP line. There were unfavourable correlations (P<0.05) between OCDf and performance in the LP line. There were numerically negative correlations between length of the small intestines (LSI) and feed conversion ratio in both lines, and a numerically positive correlation between LSI and daily weight gain in the HP line. There were no interactions between selection lines and test diets. The present results indicate that selection for LTGR ought to be performed on a high protein feeding r...

Effect of selecting for increased lean tissue growth rate in swine on low or high dietary protein levels.

To determine the optimum nutritional status when selecting for increased daily lean tissue growth rate (LTGR) two selection lines of Swedish Yorkshire pigs were tested for responses and interactions when fed three diets that contained .70, .85, or 1.00% lysine and 13.9, 15.8, or 17.5% CP, respectively. Selection for increased LTGR was made while the pigs were fed diets with low CP (13.1%) and lysine (.64%) (LP line) or high CP (18.5%) and lysine (.96%) (HP line) concentrations. Two experiments were performed after three generations of selection, with pigs fed from 25 to 105 kg BW. The animals were fed restrictedly on an energy basis in relation to BW. A total of 236 pigs were tested. When testing main effects of selection line, the HP line had superior average daily lean tissue gain (P = .031), carcass lean percentage (P = .007), and lean to feed ratio (P = .028) compared with the LP line. No diet x genotype interaction was found for any of the traits tested. The selection in the HP line resulted in faster genetic progress because this line had best overall performance. This supports the theory that the most efficient selection is achieved in an environment that enables the animals to express their genetic capacity for the desired trait.