Vloga skeleta kokoši pri prireji jajc

Zagožen, Špela (author), Terčič, Dušan (mentor)

Kokoši nesnice imajo tri tipe kosti, od katerih sta dva tipa namenjena strukturni podpori telesa (kortikalne in trabekularne kosti) medtem ko tretji tip, medularne kosti, služi kot pomemben vir kalcija, ki je poglavitni sestavni del jajčne lupine. Količina kalcija, ki se bo iz teh kosti porabila za oblikovanje lupine je odvisna od količine kalcija, ki se absorbira iz prebavnega trakta v času tvorbe lupine. Če količina prehranskega kalcija ne zadostuje, se kalcij, potreben za oblikovanje lupine, sprosti iz kortikalnih kosti. Funkcije kalcija so povezane s fosforjem in vitaminom D3. Fosfor je pomemben za obnavljanje medularnih kosti, medtem ko je aktivna oblika vitamina D3 1,25-dihidroksiholekalciferol ključnega pomena za črevesno absorpcijo kalcija in fosforja. Ravnotežje elektrolitov v prehrani je prav tako pomemben element ohranjanja kakovostne lupine, saj ima vpliv na mineralizacijo lupine. Kost je dinamično tkivo, ki se tudi pri odraslih živalih nenehno preureja in ponovno modelira. Na rast kosti in ponovno modeliranje vpliva več vrst celic (npr. osteoblasti, osteoklasti, hondrociti) in številni hormoni (npr. rastni hormon, tiroksin, melatonin, estrogen, kalcitonin, paratiroidni hormon). Na račun kortikalnih in trabekularnih kosti se s trajanjem nesnosti povečuje volumen medularnih kosti, glavni promotor teh sprememb pa je hormon estrogen. Neustrezna prehrana in nekatere bolezni dihal ter prebavil so glavni razlogi za neustrezno celovitost skeleta in težave s kakovostjo jajčne lupine.

• Language: Slovenian
• Keywords: kokoši, nesnice, skelet, jajca, prireja
• Work type: Bachelor thesis/paper
• Organization: BF - Biotechnical Faculty
• Year: 2019
• PID: 20.500.12556/RUL-111387
• COBISS.SI-ID: 4302472
• Publication date in RUL: 29.09.2019

Secondary language

• Language: English
• Title: The role of the laying hen skeleton in egg production

Abstract

Laying hens possess three forms of bone, two of which are dedicated to structural support (cortical and trabecular bone) and one form, known as medullary bone serving as an important source of calcium which is the primary component of the egg shell. The amount of calcium that will be used from these bones to form the shell depends on the amount of calcium absorbed from the digestive tract during the shell formation. If the amount of dietary calcium is insufficient, the calcium required to form the shell will be mobilized from the cortical bones. Functions of calcium are associated with phosphorus and vitamin D3. Phosphorus is important for replenishing the medullary bone while active form of vitamin D3 1,25-dihydroxycholecalciferol D is essential for the intestinal absorption of calcium and phosphorus. Dietary electrolyte balance is also an important consideration for shell quality as it can influence the mineralization of the shell. Bone is a dynamic tissue which is continually being re-organised and re-modelled even in mature animals. Bone growth and re-modelling are affected by several cell types (e.g. osteoblasts, osteoclasts, chondrocytes) and by many hormones (e.g. growth hormone, thyroxine, melatonin, estrogen, calcitonin, parathyroid hormone). At the expense of cortical and trabecular bones, the volume of medullary bones increases with the duration of laying, and the main promoter of these changes is the hormone estrogen. Inadequate nutrition and some respiratory and digestive diseases are the main reasons for inadequate skeletal integrity and problems with egg shell quality

• Keywords: laying hens, skeleton, eggs, production