Indoor fattening of lambs raised on pasture: 2. Influence of stall finishing duration on triglyceride and phospholipid fatty acids in the longissimus thoracis muscle.

Twenty-four male Ile-de-France lambs (six blocks of homologous lambs) were used to study the effect of four feeding systems on muscle triglyceride (TG) and phospholipid (PL) fatty acids (FA) from the longissimus thoracis (LT): raised and finished on cool season grasses (G), raised on the same grasses and stall-finished, indoors, on concentrates and hay, respectively, for 22 (GSS) and 41 days (GSL), and stall-feeding, indoors, on concentrate and hay during both growing and finishing periods (S). In TG, similar decreases (P<0.05) of proportions of linolenic acid were observed after changing from grass feeding to stall feeding (GSS and GSL), and a decrease (P<0.05) in proportions of conjugated C18:2 cis9, trans11 (CLA cis9, trans11) was obtained after a long period of concentrate feeding (GSL). In PL, C22:5 n-3 achieved a significantly (P<0.05) lower level in GSL lambs compared both G and S lambs. A similar non-significant tendency was observed in the case of the other very long chain n-3 polyunsaturated FA. The separate analysis of fatty acids of TG and PL from the LT muscle underlined that TG afforded a more significant lowering effect than PL on the overall ratio between C18:2 n-6 and C18:2 n-3 in muscle lipids and on the health potential of meat for the consumer. A PCA analysis combining FA composition of TG and PL, and growth performances of the lambs allowed an efficient discrimination between the four feeding systems.

Indoor fattening of lambs raised on pasture. Part 1: Influence of stall finishing duration on lipid classes and fatty acids in the longissimus thoracis muscle.

Forty male Ile-de-France lambs (10 blocks of 4 homologous lambs) were used to study the effects of four feeding systems on muscle fatty acids (FA): raising and finishing on cool-season grasses (G), raising on the same grasses and stall-finishing, indoors, on concentrates and hay, respectively, for 22 (GSS) or 41 days (GSL), and stall-feeding indoors on concentrates and hay during both growing and finishing periods (S). Twenty-four lambs only (6 blocks) were retained for comparison of growth performances, lipid content in the longissimus thoracis muscle (LT) and their FA composition according to treatment. The 16 other lambs (4 blocks) were removed from the comparison, due to a large spread in the growth of the lambs towards the end of the trial. No significant effects of treatment were seen on the rate of growth (221, 228, 243 and 245±SE 8.0g/d, respectively, for G, GSS, GSL and S groups), and the lipid contents of the LT (2.22, 2.16, 2.17 and 2.52±SE 0.11g/100g fresh tissue). Grazing, lowered n-6 PUFA (polyunsaturated fatty acids), and increased n-3 PUFA and C18:2 c9t11 (conjugated linoleic acid cis9, trans11) compared to concentrate feeding. The main effects of grazing were not removed by a short period of finish indoors on concentrate (GSS group), but C20:4 n-6 and C22:6 n-3 contents achieved the lowest contents in this group, with significant differences from the values observed for GSL and S groups (C20:4 n-6) or from the three other groups (C22:6 n-3). After a longer period of finish on concentrate (GSL group), C18:3 n-3 (linolenic acid), C18:2 c9t11 and long chain (LC) n-3 PUFA were brought to the levels observed in the S group. In terms of adequacy for human health, the C18:2 n-6/C18:3 n-3 ratios were favourably low in the four groups (2.6, 3.6, 4.9 and 5.2±SE 0.7, respectively, for G, GSS, GSL and S groups), the level observed in the case of G group being significantly lower than for the three other groups and the level observed for GSS group being significantly lower than for the GSL and S groups.

Effect of grass or concentrate feeding systems and rate of growth on triglyceride and phospholipid and their fatty acids in the M. longissimus thoracis of lambs.

Thirty-two male Ile-de-France lambs were used in a factorial 2×2 design to analyse the effects of feeding systems (grass outdoor, G, or concentrate and hay indoor: stall, S) and of growth rate (low, L, or high, H) on total lipids, triglyceride (TG) and phospholipid (PL) contents and their fatty acid composition in the longissimus thoracis muscle (L.T.). Contents were lower for TG (10.4 vs. 15.8 mg/100 g fresh tissue, P<0.05) and higher for PL (6.4 vs. 5.8 mg/100 g fresh tissue, P <0.05) in grass-fed lambs compared to stall-fed ones. TG of grass fed lambs displayed lower proportions of palmitic acid (C16:0), monounsaturated fatty acids (MUFAs), linoleic acid (C18:2n-6) and other (n-6) polyunsaturated fatty acids (PUFA) and higher proportions of stearic acid (C18:0), linolenic acid (C18:3n-3), cis 9, 11 trans C18:2 and trans monounsaturated fatty acids. In PL of the same lambs only lower MUFA, C18:2n-6 and (n-6) PUFA and higher C18:3n-3, (n-3) PUFA and cis 9, 11 trans C18:2 were observed. Growth rate had no effect on lipid, TG or PL contents of longissimus thoracis. However C18:0 proportions were higher in TG and lower in PL for low growth rate lambs. Low growth rate lambs had also lower cis 9, 11 trans C18:2 in TG. Thus, irrespective of growth rate, the muscle lipids characteristic of grass fed lambs fulfilled the recommended features of human food components much better than that of stall fed lambs, namely for CLA and C18:3n-3. The lower ratios of (n-6) to (n-3) PUFA displayed in grass fed lambs both in TG and in PL were also useful to discriminate all the grass fed lambs from all the stall fed animals.

Hind-limb protein metabolism in growing sheep; effects of acute and chronic infusion of clenbuterol by close arterial and systemic routes.

1. Close arterial infusion of clenbuterol (0.7 microgram/hr) for a 3 hr period led to decreased protein synthesis and degradation (both P < 0.05) across the hind-limb of sheep. 2. Systemic infusion of the drug (14 micrograms/hr) for a similar period increased blood flow (P < 0.001) through the hind-limb and decreased protein degradation (P < 0.05). 3. Following chronic (7 day) close-arterial infusion of clenbuterol (1.9 micrograms/hr) hind-limb protein synthesis and degradation again declined (P < 0.05) but this was apparently not recovered during 7 days of drug withdrawal. 4. In consequence, during subsequent systemic infusion of the drug (62 micrograms/hr) the lower rates of protein metabolism were not altered significantly, despite improved whole nitrogen retention (+30%, P < 0.01). 5. The results are discussed with reference to the differential actions of beta-agonists on the various tissues of the hind-limb.

Effects of substitution of tricaproin for tallow and of protein concentration in milk substitutes on nitrogen and energy balance in the preruminant lamb.

1. Results of 138 nitrogen balance studies from experiments with forty male Limousin and nineteen male Ile de France preruminant lambs were used to estimate total N requirements and to assess the effects of dietary tricaproin inclusion, protein concentration, lysine and methionine supplementation and the age of lambs on protein retention. In addition, energy balances were obtained in twenty-four of the Limousin lambs from birth up to 3 weeks of age by means of a slaughter technique. 2. For milk substitute unsupplemented with amino acids, tricaproin inclusion increased N balance slightly (P less than 0.001) when a medium-protein concentration (260 g/kg dry matter (DM] was used, in 2-week-old lambs (+4.3%) and in 5-week-old Limousin lambs (+5.3%), or very markedly when a high-protein concentration (320 g/kg DM) was used, in 2-week-old lambs (+14.5%) and in 5-week-old lambs (+18.6%). Protein requirements decreased from 300 g/kg DM in 3-week-old lambs to 270 g/kg DM in 5-week-old lambs for the control milk containing tallow-coconut oil mixture (0.67:0.33 by wt) and was increased above 300 g/kg DM at all ages in the case of experimental milk containing tallow-coconut oil-tricaproin mixture (0.33:0.33:0.33, by wt). 3. For milk containing either a medium- or a high-protein concentration and supplemented with lysine and methionine, inclusion of tricaproin increased N balance (P less than 0.01) to a similar extent (+8.5 up to +14.3%) in 1 to 2- and 3-week-old Limousin lambs. An increase in N concentration in the milk had no effect in 1- and 2-week-old lambs, but led to a decreased N balance in 3-week-old lambs. Protein requirements decreased from 310 g/kg DM in 1-week-old lambs to 190 g/kg DM in 3-week-old lambs for the milk containing tallow-coconut oil or from 300 g/kg DM in 2-week-old lambs to 210 g/kg DM in 3-week-old lambs for the milk containing tallow-coconut oil-tricaproin. 4. For the Ile de France lambs given milk supplemented with lysine and methionine, tricaproin inclusion did not alter N balance. Protein requirements decreased from 370 g/kg DM in 2-week-old lambs to 270 g/kg DM in 4-week-old lambs for milk containing both kinds of fat mixtures.(ABSTRACT TRUNCATED AT 400 WORDS)

Influence of psychosomatic stress in pregnant guinea-pigs on fetal lipid metabolism.

After a psychosomatic stress applied to pregnant guinea-pigs, 7 or 1 day before term, plasma cortisol and non-esterified fatty acid levels increased immediately in mother and fetus. Plasma levels of cortisol and non-esterified fatty acids in newborns of mothers stressed 1 day before term were lower than in newborns of control mothers. The prenatal stress changed composition of triacylglycerol and phospholipids in newborn liver by inhibiting the postnatal increase of triacylglycerol and phospholipid stearic acid and by inhibiting the postnatal decrease in phospholipid palmitic, palmitoleic, linolenic and arachidonic acids.

Addition of sorbitol to a milk substitute for veal calves. I. Effects on health, growth and feed conversion.

Two homologous groups of preruminant male calves (10 control and 9 sorbitol) of the Friesian X Holstein crossbreed were used to study the effects of sorbitol on appetite, health status and growth rate. Between 1 and 8 weeks of age they were given two milk replacers (IC and IS) that contained high levels of protein and fat (23% of DM), and then between 8 and 19 weeks two diets (FC and FS) containing lower levels of protein and fat (21% of DM). The IC and FC diets had no sorbitol, while in the IS and FS diets it accounted for 0.8% of DM. In each group 4 to 6 calves were used to measure milk digestibility at 3, 7 and 12 weeks of age. At slaughter (19 weeks), carcass quality and liver status were checked. The overall health status of the animals was satisfactory, but after accidental cold stress at week 7, the 10 calves of the control group had diarrhea for 2 to 5 days vs 4 calves in the sorbitol group. Sorbitol digestibility was about 95% at week 3 and almost 100% at weeks 7 and 12. Apparent energy and protein digestibilities increased in the two lots from 83.8 and 83.1, respectively, at week 3, to 89.8 and 90.7%, respectively, at week 7, but these digestibilities were not affected by sorbitol. Liveweight gain (+ 12% for the whole trial) and feed efficiency (+ 6.7% for the whole trial) were significantly (P less than 0.05) improved by the presence of sorbitol in the diet.

Addition of sorbitol to a milk substitute for veal calves. II. Effects on plasma, liver and muscle lipids.

Two homologous groups of preruminant male calves (10 control and 9 sorbitol) of the Friesian X Holstein crossbreed were used to study the effects of sorbitol on lipid metabolism. Between 1 and 8 weeks of age they received two diets (IC, IS) with high levels of protein and fat (23% of DM), and then between 8 and 19 weeks two diets (FC, FS) containing lower levels of protein and fat (21% of DM). Diets IC and FC contained no sorbitol, while in the IS and FS diets it accounted for 0.8% of DM. Blood samples were taken at 2, 3, 4, 7, 12 and 19 weeks of age and at the following times: 2 h before (T-2), and then 1/2 (T1/2), 2 (T2), 3 (T3), 5 (T5) and 7 (T7) hours after ingestion of the morning meal. At slaughter (19 weeks), samples of liver and of rectus abdominis muscle were taken from the carcasses. The addition of sorbitol to the replacer milks had no effect on plasma levels of nonesterified fatty acids or triglycerides. However at weeks 2, 7 and 12, the levels of free and esterified cholesterol decreased significantly by a mean of 60 and 15% respectively. Sorbitol intake significantly reduced muscle levels of triglycerides (6.8 mg/g of fresh tissue vs 18.6 mg/g), free cholesterol (0.41 mg/g vs 0.66) and total lipids (13.6 mg/g vs 26.1). Lipid composition of liver was not modified by sorbitol ingestion. An histological study confirmed that the diets caused no serious lesions. Generally, the results were more dispersed in the control group than in the sorbitol group.

[Effect of the replacement of a part of the tallow in a milk supply with tricaprylin or coconut oil on the use of energy and nitrogen by the preruminant calf]. / Influence du remplacement d'une partie du suif d'un aliment d'allaitement par de la tricapryline ou de l'huile de coprah sur l'utilisation de l'énergie et de l'azote par le veau préruminant.

The advantages of using caprylic acid in the feed of preruminant calf have been investigated and compared to those of coconut oil. Two trials were carried out. Trial 1 studied the effect on the appetence and digestibility of a conventional milk replacer when tricaprylin ( TC8 ) was substituted for one-half of the tallow in the replacer. Trial 2 investigated diet digestibility and energy and nitrogen balances in 3 groups of 6 Friesian male preruminant calves each, using two open-circuit respiratory chambers. Group 1 was fed a control diet based on skim-milk powder and tallow (diet 1). In group 2, 2/3 of the tallow was replaced by coconut oil (diet 2). In group 3, 1/3 of the tallow was replaced by coconut oil and the other 1/3 by TC8 (diet 3). Apparent digestibility of energy (94.4 vs 90.7%; P less than 0.05) and nitrogen (93.2 vs 89.7%; P less than 0.10) and energy metabolizability , q (91.6 vs 88.1%, NS) were higher with diet 2 than with diet 1. TC8 intake also favoured a higher apparent digestibility of energy (98.0 vs 92.9%; P less than 0.01) and nitrogen (96.9 vs 93.0%; P less than 0.001) in trial 1 but not in trial 2 where diet 3 had only a slightly higher apparent digestibility than diet 1 (92.9% for energy and 90.7% for nitrogen; P less than 0.10). Adjusted protein gains observed in trial 2 were 52.3 +/- 3.4, 58. 9b +/- 5.3 and 56. 5ab +/- 5.4 kcal/d/kg W0 .75, respectively, for each of the 3 diets; adjusted lipid gains were 66. 8a +/- 4.0, 59.6b +/- 4.2 and 61. 2ab +/- 6.7 kcal/d/kg W0 .75; and adjusted energy gains were 119.2 +/- 6.2, 118.4 +/- 6.1 and 117.5 +/- 6.6 kcal/d/kg W0 .75 (a, b = data with different superscripts are significantly different; P less than 0.05). Metabolizable energy (EM) efficiency for tissue deposition was of the order of 0.67 +/- 0.14, and maintenance requirements amounted to an average of 95 kcal EM/d/kg W0 .75.

[Effect on energy and nitrogen balances of replacing part of the tallow in a milk replacer for preruminant calves by tricaproin or coconut oil: effect of previous feeding level]. / Influence du remplacement d'une partie du suif d'un aliment d'allaitement par de la tricaproïne ou de l'huile de coprah, sur l'utilisation de l'énergie et de l'azote par le veau préruminant; influence du niveau d'alimentation antérieur.

Using two open-circuit respiratory chambers, the effects of medium chain fatty acid intake on digestibility, energy and nitrogen balance were investigated in 4 groups of preruminant Friesian male calves. One group of 7 animals was fed a control diet with a skim-milk powder and tallow base (diet 1). The other three groups were fed diets in which one-third of the tallow was replaced by either 1/3 coconut oil (6 animals, diet 2) or 1/3 tricaproin (6 animals, diet 3). In diet 4, two-thirds of the tallow was replaced by 1/3 coconut oit + 1/3 tricaproin (5 animals). Apparent digestibility and energy metabolizability (q) were similar for diets 1, 2, 3 and significantly higher (P less than 0.05) for diet 4: 97.5 vs 95.1% for dry matter digestibility 97.3 vs 94.5% for energy digestibility, 95.6 vs 93.7% for crude protein digestibility and 94.6 vs 92.8% for q. Whatever the diet, metabolizable energy (ME) efficiency for tissue deposition was 70 +/- 9% and maintenance requirements amounted to an average of 90 kcal ME/d/kgW0.75. However, the latter were related to previous feeding level and increased by .13 +/- 0.06 kcal/d/kgW0.75 for an increase of 1 kcal/d/kgW0.75 of previous ME intake. The lipids in each of the 4 diets were also deposited at a rate of 0.40 +/- 0.09 kcal. Lipid gain was decreased by 0.12 +/- 0.08 kcal for an increase of 1 kcal/d/kgW0.75 of previous Me intake. The regression coefficients of protein energy gain on Me intake were 0.25 +/- 0.01; 0.25 +/- 0.06; 0.30 +/- 0.04 and 0.29 +/- 0.06 kcal PF/kcal of ME, respectively, for protein gain did not depend on the previous level of ME intake. Finally, for each of the four diets, respective adjusted energy gains were 107.5a; 122.6b; 105.6a and 99.1a kcal/d/kgW0.75, adjusted lipid gains 60.4a; 69.0a; 50.9b and 42.6c kcal/d/kgW0.75 and adjusted protein gains 47.6a; 53.6b; 53.8b and 57.5c kcal/d/kgW0.75 (data with a different superscript are significantly different; P less than 0.05). In the present study, the energy cost of protein deposition amounted to 2.29 +/- 0.21 kcal ME/kcal of protein and that of lipid deposition to 0.99 +/- 0.20 kcal ME/kcal of lipid.

Postprandial lipids in blood plasma of preruminant calves.

Four 3-wk-old calves were fed twice a day a milk replacer containing 21% tallow. Lipids in blood plasma were studied for 7 h after the morning meal. Fatty acid concentration in each class of lipids was determined by internal standard procedure. Results were homogenous among animals. Postprandial time had a highly significant effect on both qualitative and quantitative aspects of fatty acids in plasma. A considerable increase in phospholipemia and ester cholesterolemia was seen 5 h after the meal. Increases in triglyceridemia were seen both 3 and 7 h after the meal. The former was related to highly saturated triglycerides resembling alimentary triglycerides. Two hours after the meal, the nonesterified fatty acid pattern showed high saturation.

[Effect of substituting coconut oil for part of the tallow in milk replacement diet on the postprandial formation of plasma lipids in young preruminant calves]. / Influence du remplacement d'une partie du suif par de l'ihuile de corprah dans l'aliment d'allaitement sur l'évolution postprandiale des lipides plasmatiques du jeune veau préruminant.

The effects of coconut oil intake on fatty acid composition and plasma content of lipids have been investigated in Friesian preruminant male calves (3-weeks-old) 2 h (T2), 3 h (T3), 5 h (T5) and 7 h (T7) after the morning meal. Calves were fed for 21 days a milk replacer containing 21 p. 100 of dry matter which comprised tallow (diet T), or 2/3 tallow +1/3 coconut oil (diet A) or 1/3 tallow + 2/3 coconut oil (diet B). Compared with the data in the case of the conventional diet (diet T), plasma triglycerides (TG) and non esterified fatty acids (NEFA) concentrations were much higher with diet A (10 p. 100 C12 +C14 acids) and much lower with diet B (30 p. 100 C12 + C14 acids). Cholesteryl esters (CE) and phospholipids (PL) concentrations showed, at each sampling time, higher values with diets A or B. C12 and C14 acids were only present in plasma NEFA and TG with diets A and B. Saturation degree of plasma NEFA and TG was very high. It reached the highest value in the TG at T3 with diets T and A, at T5 with diet B. The fatty acids composition of plasma TG was only similar at T7 to that of feed TG (diet T, A or B). The fatty acid composition of plasma PL and especially CE was characterized, for the 3 diets, by the high level of polyunsaturated fatty acid proportions.