The transmission of melamine from feed to poultry products

Basson, Petronella Elizabeth (2011-03)

Thesis (MScAgric (Animal Sciences))--University of Stellenbosch, 2011.

Includes bibliography.

Thesis

ENGLISH ABSTRACT: Two studies were done to determine the distribution rate and efficiency of dietary melamine (MEL) to poultry meat and eggs. The possibility of MEL distribution into meat and eggs after feeding cyromazine (CYR) was also investigated. Five separate diets were formulated for broiler and layer chickens containing graded levels of MEL. In the broiler trial (Experiment 1), a number of 480 day-old Cobb 500 broiler chickens were divided into five treatment groups. Diets contained 0 (CON), 50 (MEL50), 100 (MEL100), 500 (MEL500) mg/kg MEL or 4 mg/kg CYR (CYR4). The duration of the trial was 36 days and breast muscle, kidney and liver samples were harvested on Days 11, 13, 15, 18, 22, 29 and 36 after the start of the feeding and analyzed for MEL. For the duration of the trial, all experimental diets were presented ad libitum and feed intake, weight gain, mortality rate, feed conversion ratio (FCR), protein efficiency rate of birds and the European production efficiency rate were determined. In the layer trial (Experiment 2), 120 Hyline Silver hens (24 weeks of age) were randomly divided into five treatment groups. The treatment diets were the same as for Experiment 1. The duration of the trial was 20 days and layers received the treatment diets for the first 10 days after which the control diet was provided for another 10 days. Feed intake, mortality rate, egg production and egg weights were recorded daily, while live weight was recorded at the beginning and end of the trial. Dietary MEL levels of up to 500 mg/kg did not have any detrimental effect on production parameters for broilers. In the layer trial, feed intake and egg weights were negatively affected by the MEL500 treatment. Dietary MEL was absorbed by broilers and layers and rapidly distributed to the kidneys, livers, muscles and eggs. As the dietary MEL concentration increased from 50 and 100 mg/kg to 500 mg/kg, an increase (P < 0.01) was observed in muscle tissue and egg MEL residue concentrations. Melamine concentration for broilers peaked at 22 days of age and decreased until day of slaughter. The kidneys contained the highest MEL residue levels, compared to other organ tissues, such as muscle and liver. In layer hens, a MEL distribution plateau in eggs was reached between Days 1 and 4 and decreased from Day 7 to 10. The distribution of MEL in eggs was higher to albumin than to the yolk. Upon withdrawal, MEL concentration in these tissues declined to undetectable levels within seven days. No MEL could be detected in meat or eggs when birds received the CYR4 treatment. The distribution efficiency (DEf) of MEL to meat and eggs did not appear to be dose dependant. For meat, the DEf varied between 1.2 and 2.7% and for eggs it varied between 0.7 and 0.8%.

AFRIKAANSE OPSOMMING: Twee studies is uitgevoer om die verspreidings tempo en effektiwiteit van melamien (MEL) na hoender vleis en -eiers te bepaal. Die moontlikheid van MEL verspreiding na vleis en eiers deur die voeding van cyromazien (CYR) is ook ondersoek. Vyf aparte diëte is geformuleer vir braaikuikens en lê-henne wat verskillende MEL insluitings vlakke bevat het. Vir die braaikuiken proef (Eksperiment 1), is 480 dag oud Cobb 500 braaikuikens ingedeel in vyf behandelings groepe. Diëte het 0 (CON), 50 (MEL50), 100 (MEL100), 500 (MEL500) mg/kg MEL en 4 mg/kg CYR (CYR4) bevat. Die tydsduur van hierdie proef was 36 dae en bors-, spier-, nier- en lewer monsters is ingesamel op Dae 11, 13, 15, 18, 22, 29 en 36 wat geëvalueer is vir MEL. Tydens die verloop van die proef is alle eksperimentele diëte ad libitum gevoer en voerinname, massa toename, mortaliteit, voeromsettings verhouding, proteïen effektiwiteits tempo asook die Europese produksie effektiwiteits tempo is bepaal. Vir die lê-hen proef (Eksperiment 2), is 120 Hyline Silver henne (24 weke oud) ewekansig verdeel in vyf behandelings groepe. Die behandelings diëte het dieselfde MEL en CYR konsentrasies bevat as Eksperiment 1. Die tydsduur van hierdie proef was altesaam 20 dae waarvan henne behandelings diëte vir die eerste 10 dae ontvang het, waarna henne vir die daarop volgende 10 dae ‘n kontrole dieët wat 0 mg/kg MEL bevat gevoer is. Voerinname, mortaliteit, eier produksie en eier gewig is daagliks opgeteken, terwyl lewende massa aan die begin en einde van die proef gemeet is. Melamien dieët vlakke tot 500 mg/kg het geen negatiewe effek op braaikuiken produksie parameters gehad nie. Vir lê-henne, is slegs voerinname en eier gewig negatief beïnvloed vir MEL500. Melamien is na inname geabsorbeer deur braaikuikens en lê-henne en het vinnig versprei na die niere, lewer, spiere en eiers. Soos die MEL vlakke van die behandelings diëte toegeneem het van 50 en 100 mg/kg na 500 mg/kg, het ‘n beduidende (P < 0.01) toename in spierweefsel en eier MEL residu konsentrasies voorgekom. Melamien konsentrasies vir braaikuikens het gepiek op 22 dae en geleidelik afgeneem tot op dag 36. In lê-henne het ‘n MEL verspreidings platu in eiers plaasgevind tussen Dag 1 en 4 en geleidelik afgeneem tydens Dag 7 en 10. Die niere het die hoogste MEL residu vlakke bevat in vergelyking met die lewer- en spierweefsels. Die verspreiding van MEL in eiers was hoër na die albumien as na die dooier. Tydens onttrekking het die MEL konsentrasie vlakke in hierdie weefsels in so ‘n mate afgeneem dat dit onbespeurbaar was binne sewe dae. Geen MEL kon in vleis- en eiermonsters gemeet word vir CYR4 nie. Die verspreidings doeltreffendheid (DEf) van MEL na vleis en eiers was nie dosis afhanklik nie. Vir vleis het die DEf gevarieër tussen 1.2 en 2.7% en vir eiers tussen 0.7 en 0.8%.

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