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dc.contributor.authorSarmiento Franco, Luis Armandoen
dc.date.accessioned2018-05-14T10:16:03Z
dc.date.available2018-05-14T10:16:03Z
dc.date.issued2001en
dc.identifier.urihttp://hdl.handle.net/1842/29985
dc.description.abstracten
dc.description.abstractA series of experiments were carried out with the aim of evaluating chaya (Cnidoscolus aconitifolius) leaf meal (CLM), a fibrous protein-rich foodstuff, in terms of both digestibility and poultry performance as a potential ingredient to be utilised in poultry diets. In the first experiment, chaya plants at either 4, 8 or 12 weeks of regrowth were harvested. With the exceptions of ether extract and oxalic acid, no differences in chemical composition of the leaves were found between the different ages of re-growth for the contents of dry matter, crude protein, neutral detergent fibre, acid detergent fibre, lignin, ash, or hydrogen cyanide. In experiment two, true metabolisable energy (TME) content as well as TME corrected to nitrogen equilibrium (TMEN) and dry matter and nitrogen digestibilities in CLM were evaluated in commercial broilers and criollo chickens. Neither CLM inputs nor genotype of the bird significantly affected the TMEn values. The collection period of droppings and the body weight of the bird significantly (P<0.05) affected TMEN. In experiment three, the effect of different fibre sources on endogenous losses of nitrogen, uric acid and amino acids as well as on energy balance and body weight loss were evaluated in cockerels. The different fibre sources caused significant (P<0.05) differences in all the dependent variables. An important fact, demonstrated by experiments 2 and 3, was that the endogenous losses of birds showed a very high variation; however, possible explanations for those findings were put forward. In experiment four, TME, net energy and heat increment values of CLM and wheatfeed were determined using cockerels in calorimeter chambers. Lower (P<0.05) values of TME and net energy were found in CLM compared with wheatfeed, and that was attributable to the different chemical composition of the ingredients evaluated and to the different properties of their fibre. In experiment five, the effect of different amounts of dietary CLM on apparent metabolisable energy (AME) of diets and on dry matter, nitrogen and amino acid digestibilities in broilers was evaluated. There were three experimental diets (0, 150 and 250 g/kg CLM) which were fed to the broilers from 1 to 21 days of age. AME and all the dependent variables were significantly (P<0.05) affected by dietary CLM contents, in both 7- and 21-day-old birds. There were higher values for all dependent variables in birds aged 21 days than in those aged 7 days. There were no differences between the control diet and CLM 150 g/kg diet for amino acid digestibility, with the exceptions of alanine, arginine and proline. However, amino acid digestibility was lower (P<0.05) in the diet containing 250 g/kg CLM than in either control or 150 g/kg CLM diets. In experiment six, the effect of adding the enzymes B-glucanase and pectinase on amino acid digestibility of CLM was evaluated in broilers. Ileal samples were collected from birds given two doses of CLM by tube feeding. Only the pectinase treatment increased (P<0.05) lysine and total amino acid digestibility. In experiment seven, the performance of broders fed different CLM dietary amounts was evaluated. Two studies were carried out in this experiment. The performance parameters of birds decreased as CLM in diets increased to 350 and 250 g/kg in the first and second studies respectively, and this was attributable to the fibre content of CLM rather than to its oxalic acid and hydrogen cyanide contents. The length and weight of caeca were greater (P<0.05) as dietary CLM increased, but the weight of the gizzard showed the opposite tendency. It was concluded that CLM is an alternative ingredient for inclusion in diets for broilers, mainly in small-farm systems. It represents an acceptable source of amino acids but it contains low concentrations of both metabolisable and net energy as would be expected in a high-fibre foodstuff.en
dc.publisherThe University of Edinburghen
dc.relation.ispartofAnnexe Thesis Digitisation Project 2018 Block 18en
dc.relation.isreferencedbyAlready catalogueden
dc.titleEvaluation of Chaya (Cnidoscolus aconitifolius) leaf meal as an ingredient in poultry diets : its availability and effect on the performance of chickensen
dc.typeThesis or Dissertationen
dc.type.qualificationlevelDoctoralen
dc.type.qualificationnamePhD Doctor of Philosophyen


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