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Biomedical subjects

M Lessire

Publications and source records attributed to M Lessire.

17 recordsLinked to original sources
PubMed2006

Broiler short-term feed preferences measured with SRAbox, a new feed choice procedure.

Three dietary compositions and 3 methods of pellet preparation were used in different choice situations to improve our understanding of the factors perceived by broiler chickens in the physical structure of their diet. Within the same visual field, broiler chickens were offered 8 microfeeders containing different pelleted feeds that could be reached from the same position of the bird. Chickens were daily tested during 5-min tests following a 45-min period of feed withdrawal, after adaptation to individual cages and experimental feeders. Two feeds (4 microfeeders/feed in alternate positions) were weighed prior to and after the test. Behavior of the chickens was videotaped during the test to count the number of pecks given to each microfeeder. In a first experiment, 2 feeds of distinct composition were either steam or cold-pelleted. The tests of choice were repeated daily from 22 to 25 and from 35 to 38 d of age on 96 male broiler chickens. Significant preferences were measured from the first test. Similar preferences were measured when chickens received the same choice or alternating choices from one test to another. Differences of feed intake between 2 feeds during 5 min were significantly correlated to differences of number of pecks (R2 = 0.85). In most cases, preferences were established within the first minute of pecking. Steam pellets were significantly preferred to cold pellets for one feed composition but not for the other. Preferences for compositions were consistent whatever the pellet preparation and probably associated with the color of the feeds. A second experiment confirmed that 38-d-old broiler chickens seemed to prefer light colors. Short-term preferences of a chicken for a feed were rather influenced by physical characteristics of feed particles (size, color, hardness) than by the origin of raw materials. Feed pecking may change because of feed composition itself, because of its consequences on color or texture cues, or both.

Animal Feed↗
PubMed2006

Short-term number of pecks and feed intake levels: a link with the physical characteristics of feed in four-week-old turkeys.

Short-term reactions of young turkeys to changes in the physical characteristics of their feed sometimes give rise to problems of adaptation in the field. Specific feeders were designed for this study to automatically count the number of pecks given at feed by 4-wk-old male turkeys during 95-min sessions. The lighting program was intermittent (0140L:0100D). In experiment 1, 4 series of 12 birds were tested 4 times/day from 28 to 31 d of age. Four control turkeys were consistently tested with 1 feed, and 8 experimental turkeys ate 1 of 32 commercial feeds (30 as pellets and 2 as crumbs) with a distinct feed for each test (16 replicates/experimental feed). Feed intake, total number of pecks, and pecking efficiency (mg/peck) were recorded for each test and normalized for each turkey. The effects of series, day, and test were not significant for controls. The number of pecks and pecking efficiency differed among feeds (P < 0.001) but not feed intake. Hierarchical Cluster Analysis for these variables distinguished 3 groups of feed: group 3 (6 crumb and small pellets) resulted in high pecking and low efficiency. However, group 1 (10 feeds) were pecked at less but more efficiently than group 2 (16 feeds) for similar feed intake, although the average sizes of the pellets were similar (6.23 and 6.16 mm, respectively), as were the average bulk density, hardness, resistance to abrasion, and color characteristics of the pellets for both groups. Two feeds of each of these 2 groups were compared in a second experiment for 12 turkeys receiving the 4 feeds successively each day over 4 d in varying order. The turkeys consistently pecked the feeds of group 1 less and less efficiently compared with group 2. The automated measurement of pecking, combined with a more detailed image analysis of feed particles, might enhance the evaluation of the effects of feed technology on the behavior of turkeys and thus become a useful tool for the feed industry.

Adaptation, Physiological↗
PubMed2001

Plasma lipoprotein distribution in the turkey (Meleagris gallopavo).

The plasma lipoprotein profile has been determined in fasted 7-week-old male turkeys. Lipoprotein classes were subfractionated by density gradient ultracentrifugation. According to phospholipid concentration over the density gradient, an initial peak was visible in the usual LDL density range, whereas two peaks were detected in that of HDL. As density increased, the lipid composition of particles showed an increase in cholesteryl esters and decrease in triglycerides. VLDL were recovered in the first fraction (d<1.013) on the top of the gradient and IDL in fractions 2-5 (d=1.013-1.028 g/ml). The LDL and HDL populations in the density range 1.028-1.090 (fractions 6-12) differ from that found in the other bird species analyzed under the same experimental conditions. LDL predominated in fractions 6-8 with mostly beta-motility and apoB100 as the major protein component. HDL predominated in fractions 10-12 (d=1.055-1.090 g/ml) and corresponded to the first HDL peak (HDL-(A)), with mostly alpha-mobility and apoA-I as the major protein component. Both LDL- and HDL-like particle populations were present in fractions 6-12, making the separation between the two classes of lipoproteins difficult. The second peak in the HDL density range (HDL-(B), d=1.076-1.146 g/ml) contained only HDL-type particles above d=1.090 g/ml. This points out the specificity of the lipoprotein distribution in the turkey that is unique among animals. The density limit at d=1.048 g/ml is a good compromise for the separation of LDL from HDL; however, the presence of HDL-like particles in the LDL density range, and the existence of two, and even three HDL subclasses should be taken into account in the design of further metabolic studies.

Animals↗
PubMed2000

Utilization of soybean oil and tallow in young turkeys compared with young chickens.

The experiment was conducted to determine the apparent metabolizable energy and apparent fatty acid digestibility of tallow and soybean oil (8% of the basal diet) in young (1 and 3 wk of age) turkeys compared with young chickens. At 1 wk of age, turkeys used fats, particularly saturated fats, more efficiently than young chickens (i.e., total fatty acid digestibility was 96.5 vs. 86.4% for soybean oil and 75.0 vs. 49.1% for tallow). This difference between the two species disappeared at 3 wk of age, when there was an increase (95.7 vs. 99.3% for soybean oil and 64.0 vs. 69.7% for tallow) in fat utilization in young chickens, whereas in turkeys it remained constant (96.5 vs. 99.3% for soybean oil and 75 vs. 69.3% for tallow). This result suggests a greater and earlier maturity of the digestive system for fat utilization in turkeys than in young chickens. This efficient utilization of saturated fatty acids in turkeys seemed to depend more on the fat origin than on bird age, because it remained constant with age (91.4 vs. 96%) when saturated fatty acids were provided by soybean oil, and decreased (particularly for C18:0: 5.08 vs. 35.8%) when saturated fatty acids were provided by tallow. In turkeys, fluctuations in secretion of bile salts or in lipase activity during the trial period may have caused the lower stearic acid digestibility at 3 wk of age. The present study revealed a difference in fat utilization between turkeys and young chickens. For higher validity of the digestibility of fats, it would be preferable to use turkeys to derive metabolizable energy and fatty acid digestibility of fat values in formulating turkey diets.

Aging↗
PubMed1997

Effect of high ambient temperature on feed digestibility in broilers.

The effect of chronic heat exposure on feed digestibility of broilers was investigated. Eighty 4-wk-old male chickens were brooded in individual battery cages in two controlled-environment rooms at a constant ambient temperature (22 or 32 C) until 6 wk of age. They were equally distributed into three treatments: 22 C, ad libitum feed consumption (22AL); 32 C, ad libitum feed consumption (32AL), and 22 C, pair-feeding on the daily feed intake of heat-exposed chickens (22PF). Broilers were fed either a standard corn-soybean meal diet (control diet) or a practical seasonal diet containing several ingredients including wheat, spring pea, and animal fat (summer diet). Digestibility of energy, dry matter, protein, fat, starch, and nitrogen, and total mineral balances were measured between 38 and 42 d of age. Apparent metabolizable energy content of summer diet was significantly decreased in 32AL compared to 22AL, whereas AME of the control diet did not change. Nitrogen retention was significantly reduced in 32AL birds compared to 22AL and 22PF birds, irrespective of the diet. Taking into account these differences in nitrogen balance, AMEn was reduced under hot exposure: -72 and -155 kcal for control and summer diets respectively, in 32AL compared to 22PF chickens. This reduction could be explained by a significant decrease of nutrient digestibility:protein: -4.2 percentage units irrespective of the diet, fat: -1.7 and -5.2 percentage units for control and summer diets respectively, and starch: -4.2 percentage units for summer diet. It thus appears worthwhile to take into account such reduction in digestibility to formulate practical diets for brooding under hot conditions. High quality oil and protein sources should also be used instead of low quality feedstuffs, like animal sources, in such conditions.

Animal Feed↗
PubMed1997

Effect of dietary fat on the fatty acid composition and fertilizing ability of fowl semen.

Broiler breeder roosters received two diets, containing either 5% salmon oil (SO) or 5% corn oil (CO). The diets differed essentially in their polyunsaturated fatty acid (PUFA) composition, with n-6:n-3 fatty acid ratios of 41.6 in SO and 1.5 in CO. The effects of these diets on the fatty acid composition of spermatozoa and seminal plasma, and on fertility evaluated after artificial insemination were observed. Whatever the diet, the fatty acid composition of spermatozoa showed notable amounts of 20:4n-6 (5-9%) and 22:4n-6 (15-21%). These essential fatty acids were not detected in the diets and were synthesized from 18:2n-6, which was abundant in the diet (15-16%) but low in spermatozoa (2-3%). Spermatozoa were also very rich in saturated fatty acids (39%). There was a clear influence of dietary lipids on the spermatozoa fatty acid profile: the proportion of n-3 fatty acids in spermatozoa from males fed SO compared to CO was higher (9.6% vs. 4.3%) and that of n-6 fatty acids was lower (22.4% vs. 33.3%). The fatty acid composition of seminal plasma included a higher proportion of saturated fatty acids (49%) than the proportion in spermatozoa, whereas minor fatty acids (14:0, 16:1n-7, 16:1n-9, 22:5n-3) were not detected. The influence of dietary lipids on the seminal plasma fatty acid profile was the same as for the spermatozoa, especially in the PUFA profile. In addition, the SO diet gave significantly higher fertility rates (96%) than the CO diet (91.6%). These results clearly show that the lipid composition of the diet may modify the fatty acid composition of the semen and its fertilizing ability.

Animals↗
PubMed1990

European reference method for the in vivo determination of metabolisable energy with adult cockerels: reproducibility, effect of food intake and comparison with individual laboratory methods.

1. A common reference procedure adopted by several European laboratories to determine apparent metabolisable energy corrected to zero-nitrogen balance (AMEn) is described. 2. Reproducibility has been estimated by comparing results from 4 diets measured in 7 laboratories. The standard deviations between laboratories of dry matter, gross energy, Kjeldahl nitrogen and AMEn were respectively, on average, 11.29 g/kg, 0.242 MJ/kg, 1.56 g/kg and 0.380 MJ/kg dry matter; the corresponding coefficients of variation between laboratories were 1.27, 1.29, 4.39 and 2.92%. 3. Effect of food intake was tested by comparing AMEn from birds fed either 0.90 or 0.45 of ad libitum: the amount of food intake had a negligible effect on AMEn values. Endogenous energy losses corrected (EELn) or not (EEL) to zero nitrogen balance were estimated either by regression between excreted energy and ingested energy or in fasted and glucose-fed cockerels. EELn estimated by regression was, on average, 8.7 kJ/bird/d.; it was independent of diet composition. EEL and EELn determined in fasted or glucose-fed birds were higher than those determined by regression. 4. AMEn values measured by individual laboratory procedures were very close to those obtained by the reference method, except from laboratories using a tube feeding procedure, where deviations were probably a consequence of overestimated EEL.

Analysis of Variance↗
PubMed1990

European reference method of in vivo determination of metabolisable energy in poultry: reproducibility, effect of age, comparison with predicted values.

1. Apparent metabolisable energy corrected to zero-nitrogen retention (AMEn) was measured using the European reference procedure in 9 European laboratories. Seven pelleted diets were evaluated. AMEn was measured with adult cockerels and young birds. 2. Between-laboratory standard deviations were for dry matter (DM) 12.5 g/kg, gross energy 0.085 MJ/kg DM, Kjeldahl nitrogen 0.768 g/kg DM, AMEn (adults) 0.256 MJ/kg DM, and AMEn (young) 0.337 MJ/kg DM. Corresponding coefficients of variation between laboratories were 1.42, 0.45, 2.15, 1.88 and 2.60% respectively. 3. AMEn values of experimental diets were always significantly lower when measured with young birds. This effect was more pronounced when diets contained added fat. 4. Tallow or soyabean oil were incorporated into two basal diets at 40 g/kg inclusion rate. No significant differences were observed between AMEn values of either diet with adults or young birds, suggesting that AMEn energy values of these fats are indistinguishable at this inclusion rate. 5. Similar AMEn values were obtained in young birds by estimating nitrogen accretion, either by the difference between intake and excreta nitrogen or by measuring body weight gain. Determined AMEn values were very similar to those predicted using three different regression equations.

Age Factors↗
PubMed1990

Effect of feeding technique, ad libitum, dry or wet force feeding, on the metabolisable energy values of raw materials for poultry.

1. Metabolisable energy values (AME, AMEn, TME and TMEn) of three raw materials (maize, sunflower meal and soyabean meal) were determined in adult cockerels using two classical feeding e techniques (ad libitum and force-feeding of dry food) and a new one in which birds were force-fed wet diets. 2. In the wet force-feeding assay nitrogen balances and food intakes were similar to those achieved with ad libitum feeding. The duration of the assay using wet force-feeding was only 2 d as compared to the 3 or 7 d experimental periods for the dry or the ad libitum assays respectively. 3. TMEn values were not dependent on the feeding technique used; AME and AMEn data obtained in the ad libitum and wet force-feeding assays were close to TMEn values. As expected, these values were underestimated in the dry force-feeding assay.

Animal Feed↗
PubMed1987

Interactions between fats of differing chemical content: apparent metabolisable energy values and apparent fat availability.

1. Tallow (A) and rape oil (E) were obtained for evaluation. They were blended in the ratios A95:E5, A90:E10 and A80:E20. The three blends together with the two pure fats were each included at 40, 80 and 120 g/kg into a basal diet. 2. The experimental diets were evaluated for apparent metabolisable energy corrected to zero nitrogen retention (AMEN MJ/kg) and apparent fat availability (g/kg) using 6 replicates of a cage of two male broiler chicks 14 d old and 8 replicates of a cage of one Rhode Island cross cockerel approximately 1 year old. Diets were fed for 72 h then removed for 24 h. This was followed by a 48 h period when food was available ad libitum and a further 24 h of starvation. A total collection of excreta was undertaken each 24 h for the latter 72 h period. 3. Evaluation of AMEN and apparent fat availability for the individual fat blends was achieved through both linear and quadratic regression. 4. Synergism, as demonstrated by a higher determined than calculated AMEN value, was detected with fat blends fed to chicks but not cockerels and only at rates of inclusion beyond 80 g/kg. 5. No consistent differences between AMEN determined through calorimetry or AME determined with reference to apparent fat availability multiplied by fat gross energy were detected.

Animals↗
PubMed1987

Interactions between fats of differing chemical content: apparent availability of fatty acids.

1. Tallow (A) and rape oil (E) were obtained for evaluation. They were blended in the ratios A95:E5, A90:E10 and A80:E20. The three blends together with the two pure fats were each included at 40, 80 and 120 g/kg into a basal diet. 2. The experimental diets were evaluated for apparent availability (g/kg) of the fatty acids palmitic (C16:0), stearic (C18:0), oleic (C18:1) and linoleic (C18:2) using 6 replicates of a cage of two male broiler chicks 14 d old and 8 replicates of a cage of one Rhode Island cross cockerel approximately 1 year old. Diets were fed for 72 h then removed for 24 h. This was followed by a 48 h period when food was available ad libitum and a further 24 h starvation. A total collection of excreta was undertaken for the latter 72 h period. 3. Evaluation of apparent available fatty acid (AAFA g/kg fatty acid) was achieved by linear regression. 4. All results indicated a progressive increase in AAFA with both chicks and adults for C16:0 and C18:0 with increasing proportions of the more unsaturated rape oil in the fat blends and for C18:1 and C18:2 with chicks. 5. Evaluation of AAFA by quadratic regression indicated an additional effect of rate of inclusion for C16:0 and C18:0 with chicks and adults and for C18:1 with chicks.

Animals↗
PubMed1985

A methodological study of the relationship between the metabolizable energy values of two meat meals and their level of inclusion in the diet.

The nitrogen-corrected apparent (AMEn) and true (TMEn) metabolizable energy values of a low-fat and a high-fat meat meal (MM) were studied. Adult roosters were fed ad libitum on a basal diet or a mixture of the basal diet and one of the two MM. At up to 60% incorporation, MM were introduced at the expense of corn in the basal diet. Dietary inclusion was at 5, 10, 20, 40, and 60%; birds were also force-fed pure MM. The ME of MM decreased as MM content in the diet increased. Highest AMEn were observed when the MM was 5% of the diet (3356 and 1715 kcal/kg for the high- and low-fat MM, respectively); this may have been attributable to synergism of MM and basal diet fatty acids. The lower ME observed with higher MM could result from interactions between calcium and one or both fatty acids and proteins. It is concluded that ME of MM should be measured in diets containing low practical MM. Artificially high experimental levels of 50 or 100% may lead to underestimation of the energy of MM.

Animals↗