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Title:Energy metabolism, growth performance, body composition, meat quality and boar taint compounds in immunocastrated pigs
Authors:Batorek Lukač, Nina (Author)
Čandek Potokar, Marjeta (Mentor) More about this mentor... New window
van Milgen, Jacob (Co-mentor)
Files:.pdf DOK_Batorek_Lukac_Nina_2015.pdf (19,44 MB)
 
Language:English
Work type:Doctoral dissertation (mb31)
Organization:FKBV - Faculty of Agriculture and Life Sciences
Abstract:In recent years, immunocastration, a vaccination against gonadotropin releasing hormone, has been proposed as an alternative to surgical castration of intact male pigs without anaesthesia. However, the effects of immunocastration on metabolic changes, nutritional requirements and growth potential have not been quantified. Thus in the present thesis, the meta-analytical approach was used to quantitatively synthesize the effects of immunocastration and four studies were conducted to evaluate the effects of quantitative and qualitative feed restriction on growth performance, heat production and energy metabolism, carcass and meat quality. Results show that boar taint compounds are dramatically reduced in immunocastrates, still they remain slightly higher than in surgical castrates. Immunocastrates are less feed efficient, fatter but grow more rapidly and may have better meat quality than entire males. Compared to surgical castrates, immunocastrates have superior performance with no difference in meat quality. It is more economical to fatten immunocastrates than surgical castrates, but production costs and carcass quality are less favourable than in entire males because of the huge increase in voluntary feed intake during the weeks preceding slaughter. Applying quantitative feed restriction after active immunization did not significantly affect growth performance or carcass composition; however, restrictively fed immunocastrates were closer to entire males, whereas ad libitum fed immunocastrates were closer to surgical castrates. Meat quality is also unchanged by the restriction. However, higher incidence of carcass lesions in restricted immunocastrates together with higher plasma cortisol level indicates more aggression prior to slaughter and can be considered as a negative aspect of the quantitative restriction. Total heat production, assumed to be the major factor contributing to the differences in feed efficiency of pigs, is changed after the immunocastration. Additional energy retained due to higher feed intake is directed towards lipid deposition. Increased fatness of immunocastrates is a result of increased daily lipid deposition caused by higher energy intake, lower fasting heat production and improved energy retention. Hence, dietary energy intake should be limited after immunocastration. Moreover, according to the results of the nitrogen balance study, dietary crude protein content could also be decreased. By reducing net energy concentration of the diet up to 10 % using higher fibre content, similar energy efficiency (gain to net energy intake ratio) may be achieved, with an advantage in terms of reduced lipid deposition, and no effect on growth rate after effective immunization. This is particularly important when immunocastrated pigs are fattened to higher body weights, i.e. when longer delays between full immunization and slaughter are practiced.
Keywords:pig, immunocastration, growth performance, carcass characteristics, meat quality, heat production, lipid metabolism, fat deposition, feed restriction
Year of publishing:2015
Source:Maribor
NUK URN:URN:SI:UM:DK:MUHG5AB4
Views:1268
Downloads:88
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Categories:FKBV
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Secondary language

Language:Slovenian
Title:Metabolizem energije, pitovne lastnosti, telesna sestava, kvaliteta mesa in substance vonja po merjascu pri imunokastriranih prašičih
Abstract:V preteklih letih je bila kot alternativa kirurški kastraciji merjaščkov brez uporabe anestezije predlagana imunokastracija, pri kateri gre za vakcinacijo proti gonadotropin sproščujočemu hormonu. Vendar pa učinki imunokastracije na presnovo energije, prehranske potrebe in rastni potencial imunokastratov še niso bili ovrednoteni. V sklopu doktorske disertacije smo tako s pomočjo meta-analize kvantitativno sintetizirali učinek imunokastracije in izvedli štiri poskuse, v katerih smo proučevali količinsko ter energijsko omejitev krme ter produkcijo toplote in presnovo energije pri imunokastriranih prašičih. Rezultati kažejo, da se po imunokastraciji vonj po merjascu drastično zmanjša, še vedno pa ostaja nekoliko višji kot pri kirurških kastratih. Imunokastrati manj učinkovito izkoriščajo krmo, so bolj zamaščeni, vendar hitreje priraščajo in imajo boljšo kakovost mesa od merjascev. V primerjavi s kirurškimi kastrati odlikujejo imunokastrate boljše pitovne lastnosti brez razlik v kakovosti mesa. Tako je reja imunokastratov bolj ekonomična kot reja kirurških kastratov, vendar pa so proizvodni stroški in klavna kakovost manj ugodni kot pri reji merjascev. Količinska omejitev krme po polni imunizaciji ne vpliva značilno na prirast ali klavne lastnosti, vendar so restriktivno krmljeni imunokastrati v omenjenih lastnostih bližje merjascem, imunokastrati krmljeni po volji pa kirurškim kastratom. Kakovost mesa je kljub restrikciji krme, v primerjavi s kirurškimi kastrati, nespremenjena. Višja incidenca lezij na klavnih trupih restriktivno krmljenih imunokastratov (podobna kot pri merjascih) skupaj z višjo plazemsko koncentracijo kortizola kaže na večjo agresijo pred zakolom in se lahko smatra kot negativni vidik količinskega omejevanja krme. Skupna produkcija toplote, glavni dejavnik, ki prispeva k razlikam v izkoriščanju krme med prašiči, se je po učinkoviti imunokastraciji spremenila. Dodatna naložena energija, ki je posledica večjega zauživanja krme po imunokastraciji, se usmeri v nalaganje maščob. Povečana zamaščenost imunokastratov je posledica povečanega dnevnega nalaganja maščob zaradi večjega vnosa energije, nižje proizvodnje toplote na tešče in boljšega nalaganja energije. Zato priporočamo, da se vnos energije po drugi vakcinaciji imunokastratom omeji, prav tako je glede na izsledke ocene bilance dušika, potrebno po drugi vakcinaciji omejiti vsebnost surovih beljakovin v krmi. S povečanjem količine vlaknin v obroku smo zmanjšali koncentracijo neto energije krmne mešanice do 10 % in s tem dosegli podobno energijsko učinkovitost (prirast preračunan na količino zaužite neto energije v obroku) po učinkoviti imunizaciji. S tem smo omejili nalaganje maščob in zagotovili boljšo učinkovitost prireje, kar je še posebej pomembno, kadar so imunokastrati namenjeni za pitanje na višje teže, ali ko je pričakovati daljši razmik med polno imunizacijo in zakolom.
Keywords:prašič, imunokastracija, pitovne lastnosti, klavna kakovost, kakovost mesa, produkcija toplote, nalaganje maščob, restriktivno krmljenje


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