What should I feed my Rottweiler to ensure optimal health and well-being throughout its life? Considering their robust physique and energetic disposition, are there specific dietary requirements or nutritional guidelines that one must adhere to as they mature? Should their meals primarily consist of high-quality protein sources, or is it equally important to incorporate wholesome carbohydrates and vital fats to promote overall vitality? Furthermore, how can one ascertain the appropriate portion sizes tailored to their age, weight, and activity level? Is it advisable to include commercially prepared dog foods, or should a raw food regimen be considered to provide a more natural diet? What role do supplements play in the diet of a Rottweiler, particularly in relation to joint health and skin condition? Are there particular ingredients or additives that one should avoid to prevent adverse health effects? How can one effectively transition their Rottweiler to a new dietary plan without causing digestive disturbances?