Gamma irradiator facilities can be used in a wide range of applications such as biological and chemical researches, sterilization of medical devices and products. Dose mapping must be performed in these equipments in order to establish plant operational parameters, as dose uniformity, source utilization efficiency and maximum and minimum dose positions. The isodoses curves are measured using dosimeters or computer simulations. This work evaluates the absorbed dose in the CDTN/CNEN GammaCell Irradiation Facility, using the Monte Carlo N-Particles (MCNP) code.

One hundred and sixty tambaqui fingerlings (Colossoma macropomum) (average weight of 11.01±2.08 g and total length of 7.8±0.18 cm) conditional in sixteen aquariums of 40 liters of water with temperature of 29.1±0.413ºC, density of stockage of 0.25 fingerling/l and constant aeration, with the objective to evaluate the amount of light in the productive performance of the fish. The treatments had consisted of the photoperiods: T1= 6 hours of light: 18 hours of dark (06HL:18HE), T2= 12HL:12HE, T3= 18HL:06HE and T4= 24HL: 0HE, with four repetitions each. The fingerling had been fed two times a day, with extrused commercial ration (28% of rude protein). The total volume of water was changed 40 times daily. To the end of 32 days, it was evaluated total length, standard length, height, consumption of ration, weight gain and survival. The results show that greater photoperiods had influenced positively the productive performance of tambaqui fingerlings.

Cento e sessenta alevinos de tambaqui (Colossoma macropomum) (peso médio de 11,01±2,08 g e comprimento total de 7,8±0,18cm) condicionados em dezesseis aquários de 40 litros de água com temperatura de 29,1±0,413ºC, densidade de estocagem de 0,25 alevinos/l e aeração constante, com o objetivo de avaliar a quantidade de luz no desempenho produtivo dos peixes. Os tratamentos consistiram dos fotoperíodos: T1= 6 horas de luz:18 horas de escuro (06HL:18HE), T2= 12HL:12HE, T3= 18HL:06HE e T4= 24HL:0HE, com quatro repetições cada. Os alevinos foram alimentados duas vezes ao dia, com ração comercial extrusada (28% de proteína bruta). Diariamente era trocado 40 vezes o volume total da água. Ao final de 32 dias, foi avaliado comprimento total, comprimento padrão, altura, consumo de ração, ganho de peso e sobrevivência. Os resultados demonstraram que os maiores fotoperíodos influenciaram de forma positiva o desempenho produtivo dos alevinos de tambaqui.

Two trials were conducted to determine the effects of rumen degradable protein (RDP) level and source on the duodenal essential amino acid (AA) composition of Dohne Merino wethers. The animals had ad libitum access to wheat straw (32 g crude protein (CP)/kg DM; 742 g neutral detergent fibre (NDF)/kg DM) and water. In the first experimental treatments casein provided 0, 40, 80, 120 and 160 g supplemental RDP/d. In experiment two, urea-nitrogen replaced 0, 25, 50, 75 and 100% of the true protein in the isonitrogenous treatments. Expressing essential AA concentration as a percentage of duodenal protein indicated that increasing RDP levels tended to decrease arginine, but significantly increased tryptophan concentrations. Histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, valine and total essential AA concentrations were not affected by dietary RDP level. Increasing the urea-N content of RDP supplements significantly decreased isoleucine, leucine, lysine, phenylalanine, tryptophan, valine and total essential amino acid (TEAA) concentrations. Histidine and threonine proportions also tended to decrease with higher non-protein N levels. When the essential AA profile is expressed in relation to lysine, the concentrations of histidine, leucine, phenylalanine and threonine decreased significantly. Arginine and valine showed a decreasing trend and tryptophan increased significantly as RDP levels were raised. The largest differences appeared between 0 and 40 g RDP supplementation, while the AA patterns for the rest of the treatments remained relatively constant. Substituting urea for true RDP induced a variable response in arginine and isoleucine, but did not affect any of the other AA's. Increasing RDP intakes significantly increased the duodenal flow of every essential AA, except arginine, and showed a strong tendency to increase TEAA flow as well. Replacing true RDP with urea significantly reduced the flow of methionine and tryptophan and also tended to decrease lysine availability in the duodenum. Individual AA and TEAA flow to the duodenum were also numerically decreased by a minimum of 34% as urea-N was increased. It appears that the qualitative duodenal essential AA profile in sheep fed low quality forages is relatively insensitive to RDP level or source. The daily essential AA flow to the duodenum seems to be compromised by urea substitution for true RDP.

The essential amino acid (EAA) profile of the Boer goat and Saanen kids was investigated. The EAA composition of the components differed from the whole empty body (WEB) concentration. No significant differences between the two species WEB EAA composition were found. Therefore, the average empty body EAA composition (g EAA/100 g crude protein) for goats was as follows: 5.65 arginine; 2.69 histidine; 2.94 isoleucine; 7.86 leucine; 6.83 lysine; 1.83 methionine; 3.04 phenylalanine; 5.55 threonine; 4.86 valine. This composition can serve as the ideal EAA requirements for growth in meat and milk goats.

Twenty-one lactating Saanen goats of similar milk yield and lactation number were fed one of three experimental protein diets: low UDP (160 g CP/kg DM), high UDP, low protein (128 g CP/kg DM), and high UDP high protein (160 g CP/kg DM). The aim of the study was to determine whether an increased UDP and decreased RDP content would increase production and also whether a decreased CP content and an increased UDP content would sustain the production of lactating Saanen does. The does on the low UDP diet had significantly higher feed intakes and were significantly heavier at the end of the trial period of 120 days. No differences in milk production or composition were observed. The CP intake/kg milk yield was 113 ± 0.01 g (4% butterfat). The low protein (20% less CP) high UDP diet was able to sustain a similar milk production with a significantly better conversion (29.3%) of N into milk protein than the other diets. In contrast the decrease in RDP and increase in UDP content, at the same CP level, did not improve the production potential of the does.

The effect of weaning age (42 vs. 70 days) on the feed intake and growth performance from seven to 140 days of age was investigated, using 58 male Saanen kids. Final body weight, average daily gain and feed conversion efficiency did not differ significantly between weaning ages during the creep (days 7-80), growth diet (days 81-140) or the total (days 7-140) experimental periods. Only feed intake, cumulative feed intake, dry matter (DM) intake and cumulative DM intake differed significantly in the creep (days 7-80) period. The creep intake (days 7-80) of the 42 day weaning treatment was 48%, which was significantly higher than the 70 day treatment due to creep feed replacing milk intake. Corresponding with a feed intake of 240 g/day and a total metabolisable energy intake of 295 ± 1.4 MJ/kid over the 7 to 42 day period, the kids underwent no post-weaning shock in terms of their growth performance and had the same final weight (29.9 ± 2.0 kg) as the 70 day weaning treatment at 140 days of age.

Impala (Aepyceros melampus) constitute one of the most commercially important species in game farming in South Africa. The purpose of this study was to compare the effects of day and night cropping on the meat quality characteristics of impala. Emphasis was placed on the influence of the cropping method on muscle pH45 (45 minutes post mortem), pHu (ultimate pH), pH decline, and the related influence on drip loss, cooking loss, toughness and colour of the meat in the M. longissimus lumborum. Measurements taken from 16 animals cropped at night were compared to those taken from 24 animals cropped in daytime. A mean pH45 of 6.67 ± 0.11 was recorded for the night cropped animals compared to a mean pH45 of 6.55 ± 0.23 for the day cropped animals. A mean pHu of 5.39 ± 0.08 for animals cropped at night was recorded compared to a mean pHu of 5.45 ± 0.11 for the animals cropped in the day. Regression analysis showed the rate of pH decline to be slower in the night cropped animals compared to those cropped in the day. This persisted when the pH values were adjusted to correct for ambient temperature. The cooling rate of the M. longissimus lumborum was twice as fast in the night cropped group. Shear force values and drip losses respectively, for the night-cropped animals were 19.11 ± 5.68 g/mm² and 2.93 ± 1.59%, whereas for the day cropped animals the values were 23.42 ± 8.13 g/mm² and 4.15 ± 2.34%. The results of this study indicate that night-time cropping does have a beneficial effect on certain meat quality parameters.