Normal young adult male rats were allowed to eat a diet of a specified protein content ad libitum, or were pair-force-fed the same diet twice a day. At the end of 14 days of controlled feeding, the animals were killed and analyzed for total body lipids. These analyses showed that the fat content of the force-fed animals, relative to those that ate ad libitum, became progressively greater as the dietary protein was increased in quantity from 0 to 67% of the diet. Furthermore, it was observed that force-fed animals excreted about 37% more urea nitrogen over a 7-day period than pair-fed animals eating ad libitum. Abruptly reversing the feeding habits of the rats immediately reversed the relative amounts of urinary nitrogen they excreted. The results of both types of experiments suggest that the intermediary metabolism of protein is related to feeding frequency (or load of absorbed nutrients to be metabolized per unit time). With fewer feedings but with total 24-hr intake constant, less dietary protein appears to participate in protein anabolic reactions since larger amounts of nitrogen are lost in the urine.

The objective of this study was to predict bodyweight and estimate body measurements of Limousin cattle using digital image analysis (DIA). Body measurements including body length, wither height, chest depth, and hip height of cattle were determined both manually (by measurements stick) and by using DIA. Body area was determined by using DIA. The images of Limousin cattle were taken while cattle were standing in a squeeze chute by a digital camera and analysed by image analysis software to obtain body measurements of each animal. While comparing the actual and predicted body measurements, the accuracy was determined as 98% for wither height, 97% for hip height, 94% for chest depth and 90.6% for body length. Regression analysis between body area and bodyweight yielded an equation with R2 of 61.5%. The regression equation, which included all body traits, resulted in an R2 value of 88.7%. The results indicated that DIA can be used for accurate prediction of body measurements and bodyweight of Limousin cattle.

The study was aimed at investigating the relationship between the number of cocaine-and amphetamine-regulated transcript (CART) structures present in the pyloric section of the abomasum and fat accumulation in carcasses of bulls -crosses of Polish Lowland Black-andWhite cows mated with Limousin bulls. The bulls were slaughtered at the mean age of 629 days and body weight of 597 kg. The distribution of cocaine-and amphetamine-regulated transcriptimmunoreactive in the pyloric section of abomasum was assessed on the basis of CART positive immunohistochemical reactions. Significant interdependence was found between the number of CART structures and carcass adiposity and the fat content of the longissimus lumborum muscle. The identified tendency for fat tissue increase in the carcasses was accompanied by a lower concentration of the structures. In the endocrine system cell the greatest number of immunopositive cells were found; ranging from 28.9 in animals more obese to 37.8 with the smallest amount of fat accumulated. The lowest numbers of immunopositive cells, ranging from 2.4 to 3.9 were noted in the submucous plexus layer. Slightly more structures were observed in nerve fibres and the myenteric plexus, at 2.9 and 4.7, respectively. The number of CART in the endocrine system was correlated with subcutaneous fat (-0.451) and marbling (-0.514). The amount of CART in these anatomical layers was significantly correlated with the thickness of subcutaneous fat (-0.541 and -0.636) and the weight of perinephric fat (-0.487 and -0.672). The results confirm that CART is an important neurotransmitter that participates in the regulation of fat deposition in the body. It must be stressed that the correlations with the analysed fat deposition indices concerned the adiposity indicators influencing the commercial value of carcasses and the meat traits important to the consumer.

The recorded range of changes do not affect the nutritional values of cheese, as free fatty acid content increased only slightly with ripening time. The observed tendencies towards slower proteolysis and lipolysis reactions can be partly explained by the increasing content of dry matter (lower water availability). It was shown that the proportion of fat in milk and cheese and its protein content significantly affected the hardness and melting properties of cheese. Importantly, the proportion of casein in milk was positively as- sociated with nitrogen recovery in the ripening product. It can be assumed that the activities increasing the proportion of casein in milk are an important method of improving the technological suitability and sensory quality of cheese.