Chicks were fed on diets varying in crude protein (CP) content (140 to 280 g/kg diet) in either 8 steps, experiment 1, or 6 steps, experiment 2. Protein composition was held constant in each experiment. At each protein concentration, 5 (experiment 1) or 6 (experiment 2) concentrations of lysine were tested, ranging from 40 to 60 g/kg CP. Growth rate and efficiency of food utilisation to 21 d of age responded to increasing dietary protein contents up to about 230 g CP/kg. An estimate of lysine requirement at each protein concentration was obtained by fitting a quadratic curve to the response data and calculating the dose of lysine (g/kg CP) needed to maximise either growth rate or gain/food ratio. Although no growth response to dietary protein was obtained between 240 and 280 g CP/kg, the amount of lysine needed to maximise growth and gain/food ratio over this range increased systematically when expressed as g/kg diet, but remained constant if expressed as g/kg CP. The regression of lysine required (g/kg diet) for maximum performance (growth or food efficiency) on CP (g/kg diet) was strictly linear for both responses in both experiments throughout the entire range studied (140 g CP/kg to 280 g CP/kg). The estimated lysine requirement was 0.053 of the CP in experiment 1 and 0.055 of the CP in experiment 2. It is concluded that a fixed ratio of lysine to protein should be specified in practical diet formulation, rather than a minimum dietary concentration of lysine. This would ensure that, if the dietary protein content rises above a prescribed minimum value in least-cost formulation, an appropriate adjustment will automatically be made to the lysine content of the solution.

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It is well known that sperm is a unique cell in that it has a function to be done by itself outside the body and this function is essential for species' continuity thus sperm by its power and intact structure has to reach the ova and perform the fertilization and this journey is affected by the chemical and physical factors that might increase or decrease its ability to move or fertilize or even to survive. The aim of this study is to find the effect of vibration that is a vigorous movement with high frequency for 20min on whole seminal fluid samples as an external physical factor. 40 fresh seminal fluid samples were selected. 1ml of each semen samples was placed in the bottom of conical tube; the tube was exposure to vibration waves by using a special shaker designed for this purpose for 20 min. This shaker consist of a M540 DC motor equipped with PWM controller to control the rotational speed from 5-2400 rpm. Semen analysis was done before and after subject vibration. A significant increase (P<0.05) was found in percentage of sperm active directed motility (grade A) with a non-significant increase in sluggish motility and a non-significant decrease in percentage of immotile sperms percentage. No significant changes were founded regarded sperm morphology and count. It was concluded that vibrating seminal sample for 20min increases the overall sperms activity with significant increase in percentage of highly active directed sperms.

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