THE EVOLUTIVE SIGNIFICANCE OF POLLEN USE AS PROTEIN RESOURCE BY TRIGONINI BEES (HYMENOPTERA, APIDAE, MELIPONINAE)

The origin of bees was marked by the change from the use of animal of vegetal protein to feed the larvae. The advantages of this change and the existence of some necrophagous species among the bees is discussed regarding to the poor digestibility of pollen.

Genetic parameters estimate for milk and mozzarella cheese yield, fat and protein percentage in dairy buffaloes in Brazil

The aim of this study was analyze the (co)variance components and genetic and phenotypic relationships in the following traits: accumulated milk yield at 270 days (MY270,), observed until 305 days of lactation; accumulated milk yield at 270 days (MY270/A) and at 305 days (MY305), observed until 335 days of lactation; mozzarella cheese yield (MCY) and fat (FP) and protein (PP) percentage, observed until 335 days of lactation. The (co)variance components were estimated by Restricted Maximum Likelihood methodology in analyses single, two and three-traits using animal models. Heritability estimated for MY270, MY270/A, MY305, MCY, FP and PP were 0.22; 0.24, 0.25, 0.14, 0.29 and 0.40 respectively. The genetic correlations between MCY and the variables MY270, MY270/A, MY305, PP and FP was: 0.85; 1.00; 0.89; 0.14 and 0.06, respectively. This way, the selection for the production of milk in long period should increase MCY. However, in the search of animals that produce milk with quality, the genetic parameters suggest that another index should be composed allying these studied traits.

EFFECTS OF PROTEIN-DEFICIENCY AND NATURAL INTESTINAL INFECTION WITH GIARDIA-LAMBLIA ON JEJUNAL INTRAEPITHELIAL LYMPHOCYTES IN RATS OF DIFFERENT AGES

1. The interaction between experimental protein deprivation and natural intestinal infection by Giardia lamblia was studied in terms of its effects on the intraepithelial lymphocyte (IEL) population and morphology of the jejunal mucosa of rats of different ages.2. Young, adult and old male Wistar rats received a protein-deficient diet (2% casein) or a control diet (20% casein) for 42 days. Mucosal height and the number of lymphocytes located among 500 consecutive epithelial cells (EC) along the villi or crossing the basement membrane were determined in PAS-stained jejunal fragments.3. The number of IEL increased progressively with animal age, from 14 to 25 per 100 epithelial cells, with significant differences between age ranges. However, the number of IEL did not differ between control and protein-deficient rats in any of the age groups. The proportion of lymphocytes crossing the basement membrane was approximately two-fold greater in young (2.8/100 EC) and adult (5.8/100 EC) protein-deficient animals than in their respective controls (1.6 and 2.8/100 EC). The intensity of parasite colonization was moderate, from 3 to 5/100 EC and did not differ between groups. The pattern of morphologic changes of jejunal mucosa in protozoal infection did not differ between control and protein-deficient animals in any of the three age groups.4. We conclude that intestinal infection with Giardia lamblia probably stimulated the local immune response, masking the reduction of the IEL population induced by protein deficiency. The increase in lymphocyte numbers with age may be related to prolonged antigenic stimulation promoted by infection.

Treatment of radius, ulna and humerus fractures with the aid of a bone morphogenetic protein in a giant anteater (Myrmecophaga tridactyla)

A giant anteater (Myrmecophaga tridactyla) was found with closed comminuted fractures on the fight radius and ulna and left humerus he duration of which was unknown. The animal was unable to use either of he thoracic limbs. The fractures were stabilized with 3.5-mm titanium plates and a commercially available mixture of micro lyophilized bovine cortical osseous and bovine BMP (Gen-tech(R), Baumer, Brazil) was implanted into the fractures sites. Postoperative radiographic evaluations were performed every 30 days and after four months. Bone healing was observed in all of he fractures. The animal was able to be reintroduced into its natural habitat. From his case we conclude that despite he low metabolic fate of the giant anteater, which is an inherent characteristic of this species, he treatment of radius, ulna and humerus fractures by means of plates and screws, associated with BMP on the Myrmecophaga tridactyla, was a success.

Genetic parameters estimates for milk, fat and protein yield analyzed by test day models for Murrah buffaloes in Brazil

The objectives of this study were to estimate genetic parameters for test-day milk, fat and protein yields, in Murrah buffaloes. In this study 4,757 complete lactations of Murrah buffaloes were analyzed. The (co) variance components were estimated by restricted maximum likelihood using MTDFREML software. The bi-trait animal test-day models included genetic additive direct and permanent environment effects, as random effects, and the fixed effects of contemporary group (herds-year-month of control) and age of the cow at calving as linear and quadratic covariable. The heritability estimate at first control was 0.19, increased until the third control (0.24), decreasing thereafter, reaching the lowest value at the ninth control (0.09). The highest heritability estimates for fat and protein yield were 0.23 (first control) and 0.33 (third control), respectively. For milk yield, genetic and phenotypic correlation estimates ranged from 0.37 to 0.99 and from 0.52 to 0.94, respectively. Genetic correlations were higher than phenotypic ones. For fat and protein yields, genetic correlation estimates ranged from 0.42 to 0.97.

Energy and protein requirements for maintenance and growth of Boer crossbred kids

Meat production by goats has become an important livestock enterprise in several parts of the world. Nonetheless, energy and protein requirements of meat goats have not been defined thoroughly. The objective of this study was to determine the energy and protein requirements for maintenance and growth of 34 3/4 Boer x 1/4 Saanen crossbred, intact male kids (20.5 +/- 0.24 kg of initial BW). The baseline group was 7 randomly selected kids, averaging 21.2 +/- 0.36 kg of BW. An intermediate group consisted of 6 randomly selected kids, fed for ad libitum intake, that were slaughtered when they reached an average BW of 28.2 +/- 0.39 kg. The remaining kids (n = 21) were allocated randomly on d 0 to 3 levels of DMI (treatments were ad libitum or restricted to 70 or 40% of the ad libitum intake) within 7 slaughter groups. A slaughter group contained 1 kid from each treatment, and kids were slaughtered when the ad libitum treatment kid reached 35 kg of BW. Individual body components (head plus feet, hide, internal organs plus blood, and carcass) were weighed, ground, mixed, and subsampled for chemical analyses. Initial body composition was determined using equations developed from the composition of the baseline kids. The calculated daily maintenance requirement for NE was 77.3 +/- 1.05 kcal/kg(0.75) of empty BW (EBW) or 67.4 +/- 1.04 kcal/kg(0.75) of shrunk BW. The daily ME requirement for maintenance (118.1 kcal/g(0.75) of EBW or 103.0 kcal/kg(0.75) of shrunk BW) was calculated by iteration, assuming that the heat produced was equal to the ME intake at maintenance. The partial efficiency of use of ME for NE below maintenance was 0.65. A value of 2.44 +/- 0.4 g of net protein/kg(0.75) of EBW for daily maintenance was determined. Net energy requirements for growth ranged from 2.55 to 3.0 Mcal/kg of EBW gain at 20 and 35 kg of BW, and net protein requirements for growth ranged from 178.8 to 185.2 g/kg of EBW gain. These results suggest that NE and net protein requirements for growing meat goats exceed the requirements previously published for dairy goats. Moreover, results from this study suggest that the N requirement for maintenance for growing goats is greater than the established recommendations.

Nutrient digestibility of degermed, dehulled corn, citrus pulp, and soy protein concentrate by barrows

This study was carried out to determine apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD) of DM, CP, GE, and their respective digestible content of degermed dehulled corn (Zea mays), citrus pulp, and soy (Glycine max) protein concentrate by pigs using the difference method. Thirty-two barrows (28.1 +/- 1.6 kg of BW) were fed a corn-soybean meal basal diet or 1 of 3 diets formulated by replacing 30% of the basal diet with 30% of 1 of the test feedstuffs for 11 d. Chromic oxide (0.3%) was included in the diets. Feces were collected from days 7 to 11 by grab sampling and ileal digesta were collected after pigs were slaughtered on day 12. The AID of DM and AID and ATTD of GE of degermed corn (77.4, 88.7, and 77.7%) were greater (P < 0.05) than those observed in citrus pulp (50.3, 86.5, and 55.8%) and in soy protein concentrate (63.5, 85.1, and 59.4%), which did not differ (P > 0.05). The ATTD of CP, total digestible CP, and total DE of soy protein concentrate (87.5%, 500 g/kg, and 3739 kcal/kg) were higher (P < 0.05) than the values in degermed corn (81.7%, 57.5 g/kg, and 3330 kcal/kg), which were greater (P < 0.05) than those in citrus pulp (60.5%, 39.5 g/kg, and 3223 kcal/kg). Total and ileal digestible DM, AID of CP, and ileal DE of degermed corn (782 g/kg, 673 g/kg, 70.7%, and 2913 kcal/kg) and soy protein concentrate (778 g/kg, 570 g/kg, 78.7%, and 2878 kcal/kg) were similar (P > 0.05) and greater (P < 0.05) than those in citrus pulp (737 g/kg, 436 g/kg, 50.6%, and 2081 kcal/kg). Ileal digestible CP of degermed corn (49.8 g/kg) and citrus pulp (33.0 g/kg) did not differ (P > 0.05) but were smaller (P < 0.05) than the value found in soy protein concentrate (434 g/kg). The DM and energy from degermed corn are more efficiently digested by the pig than those from soy protein concentrate and citrus pulp. Soy protein concentrate was the best protein source evaluated in this study.

Hepatic lesions in protein-deficient adult rats

Four groups of 10 young adult Wistar male rats were fed ad libitum on a protein-free diet for periods of 7, 28, 56 and 84 days. Control groups were fed on a 20% casein diet. Food intake and body weights of rats were registered. Plasma protein levels and liver weight and fat content were determined. Sections of the caudate lobe were studied histologically. Fatty changes were classified in three grades. Protein-deficient rats exhibited loss of body weight and had low levels of plasma protein concentration. Liver lost weight after 7 days of protein deficiency; there was a gradual reduction in liver weight as periods of protein deprivation were longer. After 7 days, liver fat concentration was not significantly higher than in the respective control group; it was significantly higher in all the other malnourished animals, As periods of protein deprivation were longer, fatty changes became more severe. Other hepatic lesions were found in 5 of the 10 rats submitted to the longest period of protein deficiency. One of the rats showed a diffuse cellular atrophy, 2 animals showed an extensive haemorrhagic necrosis, another showed a focal area of reticulum collapse and the last exhibited a distortion of the normal architecture of the liver due to diffuse reticulum collapse and early nodular regeneration; these 2 last rats showed early fibrosis in portal areas. The findings suggest that other deficiencies may complicate the protein deficiency when rats are given a protein-free diet over prolonged periods. Even if the protein-deficient diet has protective nutrients, it may be that, when rats eat less food, as occurs in prolonged experiments deficiency of one or all of these elements can occur, depending on their relative amount in diet.

Protein synthesis studies in skeletal muscle of aging rats. II. In vitro studies with 0.5M potassium chloride washed polyribosomes

To investigate further the age-related reduction in muscle protein synthesis activity found previously using a crude polyribosome/pH 5 system (Pluskal et al., 1984), a 0.5M KCl washing procedure was utilized to remove the nonribosomal factors from polyribosomes isolated from male Sprague-Dawley rats in the following age groups: young (1 to 2 months), mature (12 months), and aged (22 to 24 months). Using a common source of enriched elongation factor fraction from young animals, it was not possible to demonstrate any significant difference (p > .05) in protein synthesis between the 0.5M KCl-washed polyribosomes isolated from the various age groups. Using a cell-free system containing young salt washed polyribosomes stimulated by the addition of 0.5M KCl-wash fractions, however, it was shown that the mature and aged salt-wash fractions were less (p < .05) active than material from young animals. Thus, the observed decline in protein synthesis efficiency during aging may be attributed to a reduced capacity to promote initiation/elongation by the nonribosomal salt wash fractions of muscle polyribosomes.

Morphometric study of the small intestinal mucosa in young, adult, and old rats submitted to protein deficiency and rehabilitation

Linear and stereological morphometric methods were applied to the jejunal and ileal mucosa of young, adult, and old male Wistar rats submitted to protein deficiency and rehabilitation. The animals were fed ad libitum a 2% casein diet during 42 days and then received a 20% casein diet for 30 days. Food intake, body weights, and plasma protein concentrations were recorded. In the young protein deficient rats values of mucosal height, surface area, and volume of the lamina propria were significantly lower than those of their age controls in both jejunum and ileum. In adults the differences were less marked and in the old rats all parameters were found to be unaltered by the protein deficient diet. The surface-to-volume ratio showed no significant differences between control and protein deficient in all three age groups, meaning that villus pattern did not change with protein deficiency. On rehabilitation, a striking difference between jejunum and ileum was observed in the young rats; all parameters returned to control levels in the jejunum, while they remained lower than those of their controls in the ileum.

Fever response induced by intravenous and intracerebrovascular injection of pyrogen in thyroidectomised and protein-calorie malnourished rabbits

The development of a fever in response to intravenous (IV, 1.5 μg/kg body mass) and intracerebroventricular (ICV, 1.5 μg/animal) injections of Escherichia coli lipopolysaccharide (LPS) was studied in control, thyroidectomised and protein-calorie malnourished rabbits (New Zealand Whites, n = 55). ICV injection of LPS is control rabbits produced a fever response, the characteristics of which differed from those obtained after IV pyrogen injection. Thyroid deficiency caused an attenuated fever response, irrespective of whether LPS had been administered by IV or ICV injection. Protein-calorie malnourished rabbits showed a smaller fever response after IV or ICV pyrogen injections. Malnourished rabbits, refed over a period of 15 days, showed a typical biphasic fever response, but with lower magnitude than controls. The results of these experiments suggest that ICV injection of LPS is not an appropriate model for the study of fever mechanisms in disease states, and that the attenuated fever response observed in protein-calorie malnourished rabbits may be related, at least in part, to a decreased ability to produce the endogenous pyrogen interleukin-1.

Liver response to low-hexachlorobenzene exposure in protein- or energy-restricted rats

The individual effects of protein deficiency and energy restriction on liver response to low-hexachlorobenzene (HCB) exposure were investigated in adult male Wistar rats. In rats fed either the low-protein or control diet, the only effect caused by HCB was a decrease in paralysis time following an ip injection of zoxazolamine. This decrease was similar for both groups. In the animals subjected to energy restriction, HCB induced a greater decrease in paralysis time, an increase in the size of centrilobular hepatocytes, a lower liver DNA content and an increased concentration of HCB in the adipose tissue, compared with the control and protein-deficient groups. Our data suggest that energy restriction increases liver response to HCB, while protein deficiency does not impair the hepatic reaction to small doses of HCB exposure.

Effects of protein malnutrition on glucose tolerance in rats with alloxan-induced diabetes

Protein-calorie malnutrition produces glucose intolerance and reduced insulin release in response to glucose. Rats adapted to low- or high-protein diets show an increased resistance to the diabetogenic action of a single dose of streptozotocin or alloxan. To determine the effects of dietary protein level on pancreatic function, we measured serum glucose levels under basal conditions and during the oral glucose tolerance test (GTT) performed before and after a single dose of alloxan administered to rats fed a 25% or a 6% protein diet for a period of 8 weeks. The incidence of mild hyperglycemia (serum glucose > 250 mg/dl) was greater among the rats fed the 25% protein diet (81%) than among those fed the 6% protein diet (42%). During the GTT performed before alloxan administration the serum glucose levels of the rats fed the 6% protein diet were not found to be significantly different from those of rats fed the 25% protein diet. During the GTT performed after alloxan injection all rats showed intolerance to the substrate (serum glucose > 160 mg/dl 120 min after glucose administration) regardless of whether basal serum glucose was normal or high. In summary, alloxan was less effective in producing basal hyperglycemia in the rats fed the 6% protein diet than in those fed the 25% protein diet but caused glucose intolerance during the oral GTT in both groups. Thus, it seems that feeding a 6% protein diet to rats offers only partial protection against the toxic effects of alloxan.

Role of different proteolytic pathways in degradation of muscle protein from streptozotocin-diabetic rats

In vitro rates of overall proteolysis and the activities of four different proteolytic pathways (lysosomal, Ca2+ dependent, ATP dependent, and ATP independent), as well as rates of protein synthesis, were measured in soleus and extensor digitorum longus (EDL) muscles from streptozotocin- diabetic rats. In the acute phase (1-3 days) of diabetes, there was an increase in overall proteolysis that coincided with an increased activity of the Ca2+-dependent pathway in both soleus and EDL and of the ATP-dependent pathway in EDL. After longer periods (5-10 days) of diabetes, the overall rate of protein degradation decreased and reached values similar to or even lower than those of controls as a result of a reduction in the activities of Ca2+-dependent and ATP-dependent pathways. No change was detected at any time interval in the activity of the intralysosomal proteolytic system in muscles from diabetic animals. Rates of protein synthesis were already reduced 24 h after diabetes induction and decreased further thereafter. Insulin treatment restored to normal the activities of the proteolytic pathways and rates of protein synthesis.