Selection for weight gain in mice at two ages and under ad libitum and restricted feeding

1988 ◽  
Vol 75 (3) ◽  
pp. 424-431 ◽  
Author(s):  
M. S. Urrutia ◽  
J. F. Hayes
Keyword(s):  
Weight Gain ◽  
Restricted Feeding ◽  
Ad Libitum ◽  
Selection For

Pre-pubertal mammogenesis in the sheep 3. The effects of restricted feeding or daily administration of bovine growth hormone and bromocriptine on mammary growth and morphology

1986 ◽  
Vol 42 (1) ◽  
pp. 53-63 ◽  
Author(s):  
I. D. Johnsson ◽  
I. C. Hart ◽  
A. Turvey
Keyword(s):  
Growth Hormone ◽  
Weight Gain ◽  
Live Weight ◽  
Restricted Feeding ◽  
Fat Pad ◽  
Live Weight Gain ◽  
Parenchymal Tissue ◽  
Mammary Fat Pad ◽  
Ad Libitum ◽  
Plasma Gh

ABSTRACTIn crossbred female lambs reared on a concentrate diet between 8 and 20 weeks of age, a restriction in food intake to 40 g/kg body weight per day decreased live-weight gain (155 g/day) compared with that in control lambs fed ad libitum (284 g/day) and significantly reduced final live weight and the size of the mammary fat pad (P < 0·001). However, restricted lambs at 20 weeks had more total parenchymal deoxyribonucleic acid (DNA; 54·7 v. 47·5 mg) occupying a greater mass of mammary fat pad (17·0 v. 13·2 g) than control lambs (P > 0·10). Restricted feeding had little effect on mean plasma growth hormone (GH) concentrations at 12 and 18 weeks of age, but decreased plasma insulin and prolactin concentrations.In lambs fed ad libitum, daily subcutaneous (s.c.) injections of 0·1 mg bovine pituitary GH per kg live weight between 8 and 20 weeks of age significantly increased daily live-weight gain (347 g/day; P < 0·001) and also increased total mammary parenchymal DNA (71·2 mg; P < 0·10) and the mass of fat pad occupied by parenchymal tissue (20·6 g; P < 0·05), compared with the control treatment. Daily s.c. injection of bromocriptine (1 mg/day) had no effect on either body or mammary growth, but tended to reduce the effects of bovine GH when given in combination. Secretory activity was observed in the parenchymal tissue of the eight lambs receiving bovine GH alone, and also in five control lambs and three lambs receiving bromocriptine alone. Three lambs that had attained puberty by 20 weeks of age had the poorest mammary development of their respective treatment groups.Mammary gland development at 20 weeks of age was significantly correlated across treatment means with plasma GH concentrations estimated at 18 weeks of age (r = 0·95; P < 0·05), but no correlations of similar magnitude were found between individuals within treatments at 20 weeks. Strongest correlations were found among 8-week-old lambs, where mammary parenchymal DNA was positively correlated with mean plasma GH (r = 0·62) and the GH:insulin ratio (r = 0·79) and negatively correlated with the prolactin:GH ratio (r = -0·65).

Selection for lean growth and food intake leads to correlated changes in innate immune traits in Large White pigs

2006 ◽  
Vol 82 (6) ◽  
pp. 867-876 ◽  
Author(s):  
M. Clapperton ◽  
S.C. Bishop ◽  
E.J. Glass
Keyword(s):  
T Cells ◽  
Food Intake ◽  
Γδ T Cells ◽  
Restricted Feeding ◽  
Large White ◽  
Lean Growth ◽  
High Line ◽  
Immune Traits ◽  
Ad Libitum ◽  
Selection For

Genetic selection is well established as a means of improving productivity in pigs, but the effects of continued selection for increased performance on immunity are not well understood, nor are genetic relationships between performance and immunity. This study compared differences in the levels of a range of immune traits between lines of Large White pigs divergently selected for a number of productivity traits. Selection lines compared were highv. low lean growth under restricted feeding (31 high linev. 10 controlv. 38 low line pigs), high v. low lean growth underad libitumfeeding (18 high line v. 10 controlv. 19 low line pigs), and highv. low food intake (24 high linev. 26 low line pigs). Immune traits measured were total white blood cell numbers (WBC), and the numbers of leukocyte subsets: neutrophils, monocytes, eosinophils, lymphocytes, CD4+cells, CD8α+cells, B cells, γδ T cells and CD11R1+Natural killer (NK) cells. CD4+, γδ T cells and CD11R1+cells were subdivided into subpopulations that were positive or negative for the CD8α marker, and conventional CD8αhigh+cytotoxic T cells were also determined. Pigs were tested underad libitumfeeding conditions from 14 to 24 weeks, and immune traits were assessed at ages 18 and 24 weeks. Line differences were estimated using residual maximum likelihood techniques. Consistent differences in immune trait levels were evident between pigs previously selected for high and low lean growth under restricted feeding: at age 24 weeks, high line pigs had higher basal levels of WBC (39·6v. 27·8×106cells per ml, s.e.d. 2·09, for highv. low line pigs) mainly explained by higher levels of lymphocytes (25·5v. 17·3×106cells per ml, s.e.d. 1·54, for highv. low line pigs) with increased numbers of CD8α+cells (8·19v. 5·15×106cells per ml, s.e.d. 0·14) and CD11R1+cells (5·23v. 2·46×106cells per ml, s.e.d. 0·43), predominantly the CD11R1+CD8α?subpopulation ((3·20v. 1·64×106cells per ml, s.e.d. 0·11). High line pigs also had increased numbers of monocytes (2·64v. 1·83×106cells per ml, s.e.d. 0·35). Similar results were obtained at age 18 weeks. There were no consistent differences between divergent lines in pigs selected for lean growth underad libitumfeeding or food intake. This is the first report to demonstrate that selection for some aspects of performance can influence WBC and leukocyte subset numbers in pigs.

Responses in carcass composition to divergent selection for components of efficient lean growth rate in pigs

1995 ◽  
Vol 61 (2) ◽  
pp. 347-359 ◽  
Author(s):  
N. D. Cameron ◽  
M. K. Curran
Keyword(s):  
Growth Rate ◽  
Food Intake ◽  
Fat Content ◽  
Restricted Feeding ◽  
Food Conversion ◽  
Daily Food Intake ◽  
Lean Growth ◽  
Daily Food ◽  
Ad Libitum ◽  
Selection For

AbstractCarcass composition was measured after six generations of divergent selection for lean growth rate on ad-libitum and restricted feeding, lean food conversion and daily food intake in populations of Large White (LW) and Landrace (LR) pigs. There were 161 half-carcass dissections in LW pigs and for LR pigs, a double sampling procedure combined information from 53 half-carcass and 53 hand joint dissections. The performance test started at 30 kg and finished at 85 kg with ad-libitum feeding and after 84 days with restricted feeding, and pigs were slaughtered at the end of the test.In the LR population, selection for lean growth on restricted feeding increased carcass lean content (605 v. 557 (s.e.d. 19) g/kg), but there were no significant responses in carcass lean content with the selection strategies on adlibitum feeding. Selection for lean food conversion and high lean growth on restricted feeding reduced carcass fat content (201 v. 241 (s.e.d. 14) and 150 v. 218 (s.e.d. 18) g/kg), but selection for high lean growth rate with adlibitum increased carcass fat content (212 v. 185 (s.e.d. 11) g/kg). Responses in carcass composition were not significant with selection on daily food intake.In the LW population, selection for high lean food conversion or low daily food intake increased carcass lean content (539 v. 494 and 543 v. 477 (s.e.d. 11) g/kg) to a greater extent than selection on lean growth rate (509 v. 475 g/kg). Responses in carcass fat content were equal and opposite to those in carcass lean content. Selection on lean growth rate with ad-libitum feeding increased lean tissue growth rate (LTGR) (491 v. 422 (s.e.d. 23) g/day), but there was no change in fat tissue growth rate (FTGR) (206 v. 217 (s.e.d. 15) g/day). In contrast, FTGR was reduced with selection on lean food conversion (169 v. 225 g/day), but LTGR was not significantly increased (520 v. 482 g/day). Selection for lean growth rate with restricted feeding combined the desirable strategies of lean growth rate on adlibitum feeding and lean food conversion, as LTGR was increased (416 v. 359 (s.e.d. 12) g/day) and FTGR decreased (126 v. 156 (s.e.d. 7) g/day). The preferred selection strategy may be lean growth rate on restricted feeding, which simultaneously emphasizes rate and efficiency of lean growth.For ad-libitum fed LW pigs, coheritabilities for growth rate, daily food intake and backfat depth with carcass lean content were negative (-0·12, -0·22 and -0·50 (s.e. 0·05), but positive with carcass subcutaneous fat content (0·22, 0·24 and 0·50), when estimated from six generations of performance test data and carcass dissection data in generations 2, 4 and 6.

Selection for improved food conversion ratio on ad libitum group feeding in pigs

1983 ◽  
Vol 37 (3) ◽  
pp. 375-385 ◽  
Author(s):  
A. J. Webb ◽  
J. W. B. King
Keyword(s):  
Weight Gain ◽  
Live Weight ◽  
Conversion Ratio ◽  
Food Conversion ◽  
Daily Food Intake ◽  
Food Conversion Ratio ◽  
Daily Food ◽  
Group Feeding ◽  
Ad Libitum ◽  
Selection For

ABSTRACTAn experiment was conducted to show the effectiveness of selection for improved food conversion ratio on ad libitum group feeding. Selection (32 ♀♀ and 8 ♂♂) and unselected control (32 ♀♀ and 16 ♂♂ lines were maintained for seven generations at the rate of one per year. Progeny were fed ad libitum from 27 to 82 kg live weight: boars singly or in pairs, and gilts in litter groups. Selection was on pen average food conversion ratio (food/live-weight gain), recalculated as each pig reached 82 kg.In spite of selection differentials averaging 0·61 s.d. per generation, there was no response (selection minus control) in food conversion at Generation 6 (−0·03, s.e. 0·08). However, there were correlated increases in daily live-weight gain (56, s.e. 18 g), daily food intake (145, s.e. 59 g) and ultrasonic backfat (2·4, s.e. 0·4 mm). In Generation 7, 146 full-sib pairs (male castrate and gilt) were tested on ad libitum or scale (0·77 g/g ad libitum daily food intake) feeding. Line by feeding regime interactions were absent for all traits except killing-out proportion and belly thickness.The increased fatness of the selection line on ad libitum feeding was retained on the scale (2·2 v. 2·4, s.e. 10 mm), suggesting a primary difference in partition of nutrients rather than intake. The selection procedure adopted was not successful in improving food conversion, but no clear conclusions could be drawn from the experiment. Uncertainty remains as to the value of group food consumption measurements in selection programmes.

Associations of acute phase protein levels with growth performance and with selection for growth performance in Large White pigs

2005 ◽  
Vol 81 (2) ◽  
pp. 213-220 ◽  
Author(s):  
M. Clapperton ◽  
S. C. Bishop ◽  
N. D. Cameron ◽  
E. J. Glass
Keyword(s):  
Weight Gain ◽  
Food Intake ◽  
Daily Weight Gain ◽  
Restricted Feeding ◽  
Large White ◽  
Daily Food Intake ◽  
Lean Growth ◽  
Daily Food ◽  
Performance Traits ◽  
Selection For

AbstractAbstract Acute phase proteins (APP) are released into the circulation in mammals upon infection and may be used to diagnose the health status of managed populations of animals such as pigs. The current study determines APP levels in a population of apparently healthy Large White pigs from a single farm, to address two questions: (1) whether phenotypic associations can be observed between productivity and APP, indicating the effects of possible subclinical infections and (2) whether previous selection for either food intake or ‘lean growth under restricted feeding’ influences APP levels. The APP investigated were alpha1- acid glycoprotein (AGP) and haptoglobin. The APP were measured at 18 and 24 weeks of age in pigs previously selected for high lean growth (no. = 31), low lean growth (no. = 38), high daily food intake (no. = 24) and low daily food intake (no. = 26), but performing under ad libitum feeding conditions. Performance traits and APP levels were constant over the experimental period, indicating that the farm health status did not vary over time. Performance traits and APP were recorded on 119 pigs, of which 80 had both APP and performance measurements. Multiple regression analyses were used to investigate phenotypic relationships between performance traits and APP levels. Plasma concentrations of AGP were higher in 18-week-old pigs compared with 24-week-old pigs (P< 0·01) whereas haptoglobin levels did not vary according to age. Significant sex differences in APP levels were observed. Females had higher circulating levels of AGP than males at both 18 weeks and 24 weeks. Females also had higher levels of haptoglobin at 18 weeks. Levels of AGP had significant negative correlations with daily weight gain (−0·59,P< 0·01 and −0·48,P< 0·05 at 18 and 24 weeks respectively) and with daily food intake (−0·53,P< 0·01 and −0·38,P< 0·05 at 18 and 24 weeks respectively). At age 24 weeks, haptoglobin was negatively correlated with both daily weight gain (−0·35,P< 0·05) and food efficiency (−0·34,P< 0·05). Pigs selected for high lean growth under restricted feeding had higher AGP levels than pigs selected for low lean growth under restricted feeding at 18 (593v. 332 μg/ml,P< 0·01) and 24 weeks of age (313 v. 219 μg/ml,P< 0·05). Selection for daily food intake did not consistently affect AGP levels, and neither selection criteria influenced plasma haptoglobin concentrations. To conclude, we have demonstrated that amongst contemporaneous pigs of the same genotype, higher systemic AGP levels and, to a lesser extent, higher haptoglobin levels are associated with decreased performance, and that genetic selection for ‘efficient lean growth under restricted feeding’ can increase serum AGP levels.

Effect of feed restriction period and strain on growth performance and haematological indices of pullet chicks

2020 ◽  
Vol 45 (2) ◽  
pp. 88-95
Author(s):  
F. A. Adewole ◽  
O. A. Adeyemi ◽  
D. Eruvbetine ◽  
O. M. Sogunle ◽  
L.T. Egbeyale ◽  
...  
Keyword(s):  
Body Weight ◽  
Weight Gain ◽  
Feed Intake ◽  
Live Weight ◽  
Daily Weight Gain ◽  
Feed Restriction ◽  
Restricted Feeding ◽  
Final Body Weight ◽  
Final Weight ◽  
Ad Libitum

An eight weeks restricted feeding trial was conducted to investigate the effect of restricted feeding and strain on the growth performance and haematological parameters of two strains of pullet chicks. Five hundred and forty chicks comprising of Isa Brown (270) and Bovans Nera (270) strains were assigned to six treatments arranged in a 2 x 3 factorial arrangement of Isa Brown and Bovans Nera on ad libitum (R ), skip-a-day (R ) and skip-2-days (R ) restrictions per week, respectively. Final live weight and weight gain of pullet chicks reduced (P < 0.05) with increasing level of feed restriction. Chicks on ad libitum showed improved (P<0.05) final live weight and weight gain. Results showed significant (p<0.05) reduction in feed intake and body weight of chicks due to restricted feeding. The birds maintained on R feed restriction group recorded the highest significant (p<0.05) values of final body weight (544.57g), feed intake per day (33.70g/day) and daily weight gain (9.82g/day). R birds recorded significantly (p<0.05) higher values of final weight, feed intake and weight gain when compared with R birds with final body weight of 480.84g, daily feed intake of 28.42g/day and daily weight gain of 8.48g. Furthermore, Bovans Nera pullet chicks recorded significantly higher (p<0.05) final weight and daily weight gain when compared with the Isa Brown birds of same age. The R pullets had significantly higher (p<0.05) white blood cells when compared with the R and R birds. Heterophil/lymphocyte ratio (0.52) was  significantly (p<0.05) lower with the Isa brown birds.

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