A note on the effect of body condition on the voluntary intake of dried grass wafers by Scottish Blackface ewes

Foot, Janet Z.

doi:10.1017/s0003356100000386

Cited by 29 publications

(14 citation statements)

References 7 publications

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“…The theory of food intake of Emmans (1981Emmans ( , 1987 predicts that birds will get fat when offered a feed with limiting protein or an amino acid because they will overconsume energy in an attempt to consume sufficient of the limiting nutrient in the feed in an endeavour to grow at their potential. This theory has been confirmed many times (Foot, 1972;Emmans, 1981;Gous et al, 1990Gous et al, , 2012Sibbald and Rhind, 1997;Whittemore, 1998). The extent to which energy can be overconsumed depends on the amount of lipid that can be stored in the body: if the genotype is such that a large amount of lipid can be stored, then the bird will be capable of consuming relatively more of an imbalanced feed than one whose ability to fatten is limited genetically.…”

Section: Discussionmentioning

confidence: 66%

“…It is also necessary to know the extent to which the given strain can deposit lipid as a means of overcoming a nutrient deficiency: birds and animals overconsume energy in an attempt to consume sufficient of the limiting nutrient in the feed (Foot, 1972;Emmans, 1981;Sibbald and Rhind, 1997;Whittemore, 1998;Gous et al, 2012), but this overconsumption is limited by the extent to which the genotype can deposit lipid, i.e., lean genotypes are unable to compensate to the same extent as fat genotypes for a marginal nutrient deficiency, and therefore, the amino acid-to-energy ratio in lean genotypes is more critical in such strains. In addition, to calculate a bird's daily nutrient requirements, it is necessary to know whether the efficiency of utilisation of amino acids for protein growth changes during growth.…”

Section: Introductionmentioning

confidence: 99%

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The response to dietary threonine in laying-type pullets during growth

Bonato

Sakomura

Gous

et al. 2015

British Poultry Science

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1. This study aimed to provide information on the response of laying-type pullets to dietary threonine (THR) during three periods of growth prior to the onset of lay. Different batches of Dekalb White pullets were used in three separate trial periods (from 4 to 6, 8 to 11 and 13 to 16 weeks of age) using 8 dietary THR concentrations in each period, using a completely randomised design, and with each treatment being replicated 6 times, using 15 birds per replication in period 1 and 8 birds in periods 2 and 3. In period 1 the THR content (THRc) ranged from 2.3 to 7.6 mg/g, in period 2 from 1.7 to 5.5 mg/g, and in period 3 from 1.4 to 4.7 mg THR/g feed. 2. Body weight gain, food intake and the deposition of protein and lipid in the feather-free body and in the feathers were measured in each period. Linear regressions were fitted to all data falling below the break point defined by the broken stick regression, to estimate the efficiency of utilisation of THR. The maximum protein growth rate was 4.0 ± 0.2, 5.3 ± 0.4 and 3.5 ± 0.5 g/d in periods 1, 2 and 3, respectively. 3. The efficiency of utilisation of dietary THR for THR deposition in each period was the same, at 0.85 ± 0.1 mg/mg. As dietary THRc decreased, the amount of body lipid deposition increased. 4. With this information, it is possible to determine the daily requirement for THR for the potential growth of body and feather protein in growing pullets.

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Section: Discussionmentioning

confidence: 66%

Section: Introductionmentioning

confidence: 99%

The response to dietary threonine in laying-type pullets during growth

Bonato

Sakomura

Gous

et al. 2015

British Poultry Science

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“…Were this not the case, the prediction of voluntary food intake by a bird or animal given ad libitum access to food would be more difficult, as this rule is central to Emmans' (1981) food intake theory in governing the amount of body lipid that might be utilised as an energy source. The fatness of an animal has been shown to affect its voluntary food intake (Foot, 1972;Sibbald & Rhind, 1997), so an accurate prediction of changes in body lipid content during growth is necessary for forecasting subsequent voluntary food intake.…”

Section: Introductionmentioning

confidence: 99%

The performance of broilers on a feed depends on the feed protein content given previously

2012

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It has been proposed that all animals have an inherent relationship between body protein and lipid that can be described allometrically, and the hypothesis tested in the research reported here is that the animal will at all times attempt to retain this relationship. The test was accomplished by feeding broilers, of three genotypes and in two experiments, in such a way as to produce lean and fat birds that were then subjected to a range of dietary protein levels in a second feeding period, during which their performance was measured. Birds were initially offered one of two feeds with widely different protein to energy ratios until they reached a pre-defined liveweight, after which they were given one of two feed protein contents in Experiment 1 and four in Experiment 2. Their performance was monitored until a second pre-defined liveweight was reached, at which time they were killed for carcass analysis. The genotype selected to be lean, in Experiment 1, showed no response to protein level in the second period, whether they were fat or lean at the start. Conversely, the genetically fat birds showed some additional growth in males and additional efficiency in the females. Averaged across genotypes and sexes, birds initially in the fat state gained only 6.9 g lipid/d versus 13.5 g lipid/d for the nutritionally lean broilers. In Experiment 2, growth rate and feed conversion efficiency (FCE) were related directly to dietary protein content and were higher for those birds made nutritionally fat. Carcass lipid gain was lower for the initially fat birds on the three highest dietary protein treatments. All birds made fat at 880 g and 1000 g, by giving them a low protein feed, had a much reduced fat content in their subsequent gain, provided that the protein content of the feed used was sufficiently high, indicating that they were making use of the excessive lipid reserves as an energy source. The hypothesis tested cannot be rejected by the evidence presented.__________________________________________________________________________________

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“…The diameter of about 500 cells was measured and grouped into nine size classes (S1 to S9) as follows : up to 30, 30-60, 60-90, 90-120, 120-150, 150-180, 180-210, 210-240, 240-360 (Robelin, 1973 Foot (1972), Graham (1969) and Schinckel (1960) but the animals did not reach a « set point » for body weight. Forbes (1977) (1979) demonstrated that in rats the diet induced an increase in the cell number as a consequence of cellular proliferation.…”

Section: Introductionmentioning

confidence: 99%