Suplementação de colina em dietas para frangos de corte machos em fase de crescimento / Choline supplementation in diets for male broilers in the growing phase

Avaliaram-se os efeitos dos níveis de suplementação de colina em dietas para frangos de corte, de 22 a 40 dias de idade, sobre o desempenho, a composição de carcaças e fígados, bem como as características macroscópicas e histopatológicas dos fígados. O período de criação foi de um a 40 dias de idade, sendo que o período experimental foi de 22 a 40 dias de idade. Até o 21º dia de idade, todas as aves receberam a mesma ração à qual foram adicionados 400mg colina/kg. No 22º dia, os frangos foram distribuídos em cinco tratamentos, nos quais os níveis testados de suplementação de colina foram: zero, 400, 800, 1.200 e 1.600mg/kg, com seis repetições de 30 aves cada. As rações experimentais, formuladas à base de milho, farelo de soja e farinha de carne/ossos, foram isonutritivas, com exceção dos níveis de colina. O delineamento experimental foi o inteiramente ao acaso, e a estimativa da suplementação de colina foi avaliada pelos modelos de regressão. Os níveis de suplementação de colina apresentaram efeito linear pelo teste F (P<0,05) para o consumo de ração. Os demais parâmetros avaliados não sofreram influência da suplementação (P>0,05). O nível de 1.600mg colina/kg de ração resulta em maior consumo de ração de frangos de corte aos 40 dias de idade.

The effects of choline supplemental levels were evaluated in diets for broilers on performance, carcass and liver composition and liver histopathology characteristics from 22 to 40 days-old. The period of creation was one to 40 days of age, and the experimental period was 22 to 40 days-old. Until 21 days of age all birds received the same diet added to 400mg choline/kg. On day 22, broilers were allotted to five treatments (zero, 400, 800, 1200 and 1600 mg/kg), with six repetitions of 30 birds each. The experimental diets formulated based on corn, soybean meal and meat/bones meal were isonutritive, except for the choline levels. The experimental design was completely randomized and the estimation of choline supplementation was evaluated by regression models. The levels of choline supplementation showed a significant linear effect for the F test (P<0.05) for feed intake. The other evaluated parameters were not influenced by supplementation (P>0.05). The supplementation of 1600mg choline/kg in the diet results in higher feed intake of broilers at 40 days old.

Efeitos do horário de postura de matrizes pesadas sobre o rendimento de incubação / Effects of oviposition time from broiler breeders on the incubation yield

The effects of oviposition time, which represents different positions of the follicles in a sequence of posture, were studied on egg weight, chick weight, egg weight loss during incubation, hatchability, embryo mortality and infertility . A total of 19, 820 eggs, layed on the same day, from Cobb® broiler breeders aging 46-week-old were used. The eggs were classified according to the oviposition time posture (corresponding to the time of collection) from 8:30 am, 10:30 am, 12:30 pm, 14:30 pm and 16:30 pm, which represented the folowing treatments: 1st, 2nd, 3rd, 4th and 5th collects, respectively. The experimental design was completely randomized with five treatments and 36 repetitions, and each tray of 96 eggs was considered a repetition. The normal and homogeneous data were submitted to analysis of variance and means compared by Tukey test. The non-normal and non-homogeneous averages were compared by Kruskal-Wallis test. It is concluded that the time of egg laying has influence on egg weight and chick weight, but does not affect hatchability, fertility and embryonic development.

Efeito do armazenamento e da cantaxantina dietética sobre a qualidade do ovo fértil e o desenvolvimento embrionário / The effect of storage and dietary canthaxanthin on fertile egg quality and embryonic development

O presente experimento foi conduzido em lote de matrizes Cobb desde 46 até 60 semanas de idade. Os tratamentos foram definidos pelas dietas (com e sem adição de 6ppm de cantaxantina na dieta das matrizes) e pelos períodos de armazenamento dos ovos (três e sete dias), em delineamento inteiramente ao acaso, em arranjo fatorial 2x2 (duas dietas x dois períodos de armazenamento). A cantaxantina dietética elevou o escore de cor da gema de sete para 14. O armazenamento dos ovos por sete dias prejudicou a qualidade dos ovos, promoveu oxidação de ácidos graxos da gema e retardou o desenvolvimento embrionário.

This trial was done with Cobb broiler breeders. Treatments were defined by the diets (with and without 6ppm canthaxanthin added to broiler breeder diets) and periods of egg storage (three and seven days) in a completely randomized factorial 2 x 2 design (two diets x two periods of egg storage). The dietary canthaxanthin increased the yolk color score from 7 to 14. Egg storage for seven days reduced egg quality, promoted oxidation of yolk fatty acids and delayed embryonic development.

Effect of histological processing and methacrylate sectioning on the area of gill tissue in teleost / Efeito do processamento histológico e seccionamento em metacrilato sobre a área de tecido branquial em teleósteo

Deformation of biological tissues may occur during histological processing and results in loss of accuracy when quantitative information about cells, tissues and organs is necessary. In this study, the gill tissue from armored catfish (Pterygoplichthys anisitsi) was quantified in each step of processing using the stereological principles. During processing for glycol methacrylate embedding, gill tissue from shrinks significantly but regains its original dimensions after sectioning.

Deformações nos tecidos podem ocorrer durante o processamento histológico e resultar em informações errôneas quando há necessidade de dados quantitativos sobre células, tecidos e órgãos. Neste estudo, o tecido branquial do cascudo (Pterygoplichthys anisitsi) foi quantificado em cada etapa do processamento utilizando os princípios de estereologia. O tecido branquial reduziu significativamente durante processamento histológico com metacrilato, mas retornou às suas dimensões iniciais depois de seccionadas, o que indica não ocorrer nenhuma perda na informação quantitativa do tecido.

Changes in gut gross morphology of traíra, Hoplias malabaricus (Teleostei, Erythrinidae) during long-term starvation and after refeeding

Traíras (Hoplias malabaricus) adultas foram submetidas a diferentes períodos de privação de alimento (de 30 a 240 dias) e realimentadas por 30 dias após 90 e 240 dias de jejum. O comprimento do estômago permaneceu constante durante todo o tempo experimental. No entanto, o comprimento do intestino reduziu significativamente após 30 dias de jejum. O comprimento normal não foi recuperado após a realimentação. O número de cecos pilóricos não sofreu modificações significativas. Por outro lado, a espessura dos cecos diminuiu após 150 dias de privação de alimento e seu comprimento diminuiu após 180 dias. Após a realimentação, porém, os cecos pilóricos recuperaram a espessura original. Nos peixes realimentados após 240 dias de jejum, os comprimentos dessas estruturas aparentemente apresentaram crescimento compensatório, tornando-se mais longas que as do grupo controle.

The effect of hypoxia and recuperation on carbohydrate metabolism in pacu (Piaractus mesotamicus)

A study of the hematological parameters, glycogen, glucose, and lactate, and the activity of malate and lactate dehydrogenases was carried out in blood and tissues of fishes submitted to two, four, and six hours of hypoxia and recuperation. Only after 4 h of hypoxia was there a drop in liver glucose. After 6 h, a drop in lactate and a rise in glucose in practically all tissues signaled a recuperation of the metabolism, probably due to ASR (aerial surface respiration). Lactate formed during hypoxia was canalized to heart and brain for oxidation and used for neoglucogenesis. There were no changes in hematological parameters nore in the activity of malate and lactate dehydrogenases during normoxia and hypoxia, which suggest that these adaptive mechanisms may not be involved during hypoxia. Glycogen concentrations did not show variation during hypoxia either

Epithelial gill cells in the armored catfish, Hypostomus cf. plecostomus (Loricariidae)

Epithelial gill cell morphology and distribution were investigated in the armored catfish, Hypostomus cf. plecostomus, which lives in soft ion-poor Brazilian freshwaters. Pavement cells are the most abundant type of cell on both filament and lamellar epithelia and there are a great number of mucous and chloride cells between them. Mucous cells are almost covered by adjacent pavement cells and have large packed granules showing electrondense differences. No mucous cells were found on the lamellar epithelium. Chloride cell were distributed throughout both epithelia and usually have large apical surface facing the external medium and may exhibit short and sparsely distributed microvilli. The presence of chloride cells on the lamellar epithelium may be an adaptation to low ion concentrations in the water, allowing for improved ion-transport capacity of the gill. The large size of these cells increases the water-blood barrier and may affect the transference of respiratory gases. However, the negative effect on the respiratory process may be minimized by this species' ability to resort to atmospheric air to fulfill its oxygen requirements

Structural and morphological features of Piaractus mesopotamicus (Holmberg, 1887) gills

The pacu Piaractus mesopotamicus (Holmberg, 1887), is a commercially important serrasalmid fish endemic to the Paraná-Paraguay River basin, and one of the most widely cultivated native fish species in the Neotropics. As a migratory species, also inhabiting temporary pools subjected to hypoxic conditions, the species presents a high plasticity concerning respiratory adaptations. In order to supplement basic knowledge on the respiratory physiology and morphology of this species, some structural features of pacu gills, such as filament and lamellae structure, and circulatory pattern are described in this paper

Changes in lactate dehydrogenase and malate dehydrogenase activities during hypoxia and after temperature acclimation in the armored fish, Rhinelepis strigosa (Siluriformes, Loricariidae)

Lactate (LDH) and malate dehydrogenase (MDH) of white skeletal muscle of fishes acclimated to 20, 25 and 30 degrees Celsius and thereafter submitted to hypoxia were studied in different sbstrate concentrations. Significant differences for LDH and MDH of white muscle enzyme activities are described here for the first time in Rhinelepis strigosa of fishes acclimated to 20 degrees Celsius and submitted to hypoxia for six hours. LDH presented a significant decrease in enzyme affinity for pyruvate in acute hypoxia, for fishes acclimated to 20 degrees Celsius and an increase for fishes acclimated to 30 degrees Celsius.

K+ balance in rainbow trout gill and liver tissue, cell suspensions and cultured cells

Both intact gill and liver tissue from rainbow trout accumulated K+, as determined by 86Rb+ uptake, a process largely inhibited by ouabain, indicating the presence of functional NaKATPase. Cell suspensions, produced by disaggregation of gill or liver tissues, accumulated very little K+ compared to tissues (Less than 10 percent). Disaggregation resulted in depolarisation of cells with loss of intracellular K+ and although NaKATPase, as measured by 86Rb+ uptake rate, remained functional and inhabitable by ouabain, the activity was insufficient to replace the rapid K+ loss. While attached, cultured gill and liver cells showed normal K+/Na+ ratios and NaKATPase activity, but release from the substratum resulted in depolarisation and rapid K+ loss as seen in cell suspensions. These results suggest that care is required in interpreting ionic regulatory and other results from cell suspensions and that further research should be directed towards systems where cells can maintain normal ionic balance.