Rumen epithelium cell proliferation and protozoa population of cannulated Nellore cattle previously exposed either to nutritional restriction or intake of concentrate ingredients prior to adaptation to high-energy diets

• Grant number: 16/25626-8
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: May 01, 2017
• End date: April 30, 2018
• Field of knowledge: Agronomical Sciences - Animal Husbandry - Animal Nutrition and Feeding
• Principal Investigator: Danilo Domingues Millen
• Grantee: Luana Doretto Felizari
• Host Institution: Faculdade de Ciências Agrárias e Tecnológicas. Universidade Estadual Paulista (UNESP). Campus de Dracena. Dracena , SP, Brazil

Abstract

The objective of this study is to evaluate the effects either prior nutritional restriction or exposure to concentrate feedstuffs on epithelial cell proliferation and the protozoa numbers in the rumen of feedlot Nellore cattle. The treatments will be: Maintenance (forage ad libitum + mineral supplement); Restriction (forage at 1.4% body weight + mineral supplement) and Concentrate (forage ad libitum + 0,5% body weight of concentrate ingredients and mineral supplement). For the first study, it will be used 96 Nellore bulls, with average initial body weight of 380 kg. The animals will be allocated on 24 pens, blocked by weight. These animals will have theirs ruminal epithelial samples collected prior to the beginning of adaptation, and at the end of the experiment to evaluate cell proliferation by means of the technique of immunohistochemistry. This study will last 144 days, divided as follows: 32 days of pre-adaptation, wherein the treatments will be applied, and 144 days with high energy diet. For the second study, it will be used a 3 x 3 Latin's square design, with 6 20 mo-old Nelore bulls, with body weight of about 350 kg, cannulated in the rumen. This study will last 110 days, and each period will have 30 days of duration (14 days of pre-adaptation and 16 days of with high energy diet) followed by an 10 days of washout between the periods 1 and 2, and 2 and 3. The ruminal fluid will be collected and used to determinate the amount of protozoas at ruminal environment.